
Class \0SH5 
Book__ 2M^ 



Gsi}yn§\tW^ 



CfOPJfRICHT DEPOStn 






CELLULOSE, CELLULOSE PRODUCTS, 
AND RUBBER SUBSTITUTES. 



CELLULOSE, CELLULOSE PRODUCTS, 
AND ARTIFICIAL RUBBER, 

COMPRISING 

THE PKEPABATION OF CEIiLULOSE FROM WOOD AND STRAW ; MANXTFACTTTBE OF 

PARCHMENT ; METHODS OF OBTAINING SUGAR AND ALCOHOL, AND OXALIC 

ACID ; PRODUCTION OF VISCOSE AND VISCOID, NITRO-CELLULOSES, 

AND CELLULOSE ESTERS, ARTIFICIAL SILK, CELLULOID, 

RUBBER SUBSTITUTES, OIL-RUBBER, AND PACTIS. 



BY 

DR. JOSEPH BERSCH. 



AUTHORIZED TRANSLATION FROM THE GERMAN, 

BY 

WILLIAM T. BRANNT, 

EDITOR OP "THE TECHNO-CHEMICAL RECEIPT BOOK." 



I L-LUSXRA-TED BV RO RTY-O M E EN <3 RAN/I N <3S. 



PHILADELPHIA : 

HENRY CAREY BAIRD & CO., 

industriaii publishers, booksellers, and importers, 

810 Walnut Street. 

LONDON : 

KEGAN PAUL, TKENCH, TRUBNER & CO., Ltd., 

DRYDia^ HOUSE, 43, GERRARD STREET, SOHO. 

1904 



LIBRARY nf CONGRESS 

Two Cooles Rereived 

JUL 14 1904 

Cooyrlgrht Entry 




PYB 



COPYKIGHT, BY 

HENRY CAREY BAIRD & CO. 
1904. 



Printed by the 

WICKERSHAM PRINTING CO. 

53 and 55 North Queen St., 

Lancaster, Pa., U. S. A. 



PEEFACE. 



Among the raw materials which nature has placed at our dis- 
posal for industrial purposes, Cellulose has from time immem- 
orial occupied a prominent position, having from prehistoric 
days, continuously served for the production of tissues, and been, 
even for thousands of years, employed as a basis for the execu- 
tion of writings. By the development of the science of chem- 
istry, we have become acquainted with a large number of com- 
pounds, which have to be considered as derivatives of Cellulose, 
and we have learned of processes for the separation of this 
important body, in a pure form, from wood and straw. 

The nitro-compounds, which can be prepared from Cellulose, 
form the starting point for all the explosive bodies in use at the 
present time; and the nitro-celluloses themselves have led to the 
invention of processes for the production of so-called artificial 
silk and of celluloid. The discovery of the peculiar compound, 
to which the term viscose has been applied, was the initiatory 
step towards the preparation of a series of bodies of technical 
importance — solutions of cellulose having created the basis for 
the preparation of lustra-cellulose, etc. The branches of in- 
dustry thereby called into existence have in a comparatively 
short time developed into noteworthy manufactures, and scarcely 
a month passes by, without our becoming acquainted with new 
applications of the compounds derived from Cellulose. 

It would appear that the problem of the production of fer- 
mentable sugar, and thence of that of alcohol, ether, acetic acid, 
etc., from Cellulose or wood, has at present more closely ap- 
proached its final solution than it had, even a few years since; 
and by the perfection of methods for this purpose a radical revo- 
lution in certain industries may eventually be looked for. 

In consideration of the far-reaching importance to the indus- 
tries of Cellulose and the products capable of being prepared 

(v) 



VI PREFACE. 

from the latter, the author has endeavored to bring together in 
a comprehensive manner everything that has up to the present 
time become known on this subject, and it is hoped, that he has 
produced a work which gives clear explanations of all questions 
pertaining to Cellulose and the products obtainable from it, and 
which will serve as a hand-book for all who may be profession- 
ally interested — from the forester to the manufacturer of arti- 
ficial silk, lustra-cellulose and celluloid. 

By reason of their extensive use for insulating purposes for 
electric lines, etc. , substances which are available as substitutes 
for rubber have acquired great industrial importance, and a 
comprehensive description of their preparation is also here given, 
and it is believed may serve to arouse the interest of a large 
body of manufacturers. 

Dr. J. Bersch. 



CONTENTS. 



I. 

Cellulose. 



PAGE 

Distribution of cellulose throughout nature; Structure of plants; Change 
of cellulose vessels into wood vessels ....... 1 

Occurrence of cellulose; Occurrence of cellulose in the animal and veg- 
etable kingdoms; Cellulose formerly at our disposal; Straw as a mater- 
ial for cellulose; Deficiencies of pulp and paper from straw ... 2 

Employment of wood for the preparation of cellulose, a modern achieve- 
ment; Chemical nature of wood; Encrusting substance of wood; Cotton. 3 

Fruit of the cotton plant, described and illustrated; Appearance of the 
cotton fibre 4 

Cotton fibres, described and illustrated; Determination of the value of a 
variety of cotton; Short-staple and long-staple cotton .... 5 

Chemical composition of cotton; Otlier fibre-producing plants and natural 
sources of cellulose-fibres; Preparation of chemically pure cellulose 
from cotton; Properties of cellulose; Formula of cellulose ... 6 

Percentage composition of cellr' ?e; Transformation of substances in the 
living plant-organism; Conversion of cellulose into soluble substances; 
Digestibility of cellulose by carnivorous animals and human beings . 7 

Solubility of cellulose; Solvents for cellulose; Behavior of cellulose to- 
wards acids; Effect of water upon cellulose ...... 8 

Hydrocellulose and its composition; Mode of manufacture on a large 
scale of hydrocellulose .......... 9 

R. Sthamer's process for the preparation of larger quantities of hydro- 
cellulose . . . . . . . . . . . .10 

Preparation of hydrocellulose with the use of hydrochlof-ic acid; Behavior 
of cellulose towards acids . . . . . . . . .11 

Upon what the various processes for the preparation of alcohol from cel- 
lulose or wood are based; Action of sulphuric acid upon cellulose; 
Formation of amyloid .......... 12 

Action of hydrochloric acid and of sulphurous acid; Action of organic 
acids; Chemical changes effected by nitric acid; Effect of the acid 
sulphites of the alkalies and alkaline earths ...... 13 

Combinations formed by cellulose with organic acids; Behavior of cellu- 
lose towards alkalies; Action of caustic alkalies; Mercerization and its 
invention by John Mercer; Conversion of cellulose into oxalic acid . 14 

(Vii) 



Vlll CONTENTS. 

PAGE 

Behavior of cellulose at an increased temperature; Destructive distillation 
of cellulose and products formed thereby; Cellulose the basis-material 
of a large series of combinations of great technical importance . . 15 

Industrial uses of cellulose; Vegetable parchment; Cellulose sulphocar- 
bonate or viscose; Nitro-celluloses ....... 16 

Artificial silk; Celluloid; Conversion of cellulose into fermentable sugar; 
Production of cellulose; Former sources of cellulose . . . . 17 

Plants utilized for the production of- cellulose; Constitution of paper; 
First experiments for the purpose of obtaining cellulose from straw . 18 

Experiments for the purpose of obtaining cellulose from wood, and final 
success in this respect .......... 19 

Invention of a processs for the solution and destruction of the lignin or 
encrusting substance of wood; Substances used for this purpose; Ex- 
periments for the production of textile threads from cellulose; Phases 
of the historical development of the production of cellulose from wood. 20 

Possibility of obtaining cellulose from wood in the form of textile fibres. 21 

II. 

Wood-stuff or Mechanical Woob-Pulp. 
Definition of the term wood-stuff or mechanical wood-pulp; Chief use of 
wood-stuff; Origin of the fundamental idea of the process of wood 

grinding; First patents granted for the process ..... 22 

Execution of Voelter's process of wood grinding; Wood for grinding; 

Most suitable varieties of wood ........ 23 

Preparation of the wood to be ground; Machine for cutting away the 

bark, described and illustrated ........ 24 

Machines for the removal of the knots, described and illustrated . . 25 

Spliting machine, described and illustrated ...... 26 

Wood-grinding machines; Essential parts of every kind of machine for 

grinding wood ........... 27 

Voelter's grinding machine, described and illustrated . , ... 28 
A. Oser's grinding machine, described and illustrated . . . .30 

Freitag's grinding machine, described and illustrated . . . - 31 
Abadie's grinding machine, described and illustrated . . . .32 

Liebrecht's grinding machine ......... 33 

Use of hydraulic pressure for pressing the wood against the grindstone; 

Water used for grinding; Filtration of the water used for grinding . 34 
Sorting the ground mass; Sorters for sorting the wood-stuff; Voith's 

shaking sieves, described and illustrated ...... 35 

Mode of operation of the shaking sieve; Use of cylinder sieves . . 36 

The refiner, described and illustrated ....... 37 

Use of corrugated rolls for the reduction of particles of wood . . .38 

Recovery of the finest particles of pulp ....... 39 

Dehydration of the pulp; The board-machine; Mode of obtaining thor- 
oughly dried pulp 40 



CONTENTS. IX 

PAGE 

Pulp for transporting long distances; Drying apparatus; Arrangement of 
the apparatus for drying pulp ........ 41 

Properties of wood-pulp; CI. Winkler's experiments; Change of color of 
pulp 42 

Bleaching agents for pulp; Bleaching by means of sulphurous acid; Pulp 
from steamed wood; Quantities of substances which pass into solution by 
steaming different kinds of wood . . . . . . . . 43 

Combinations formed in steaming wood; Apparatus for steaming wood; 
Production of pulp from steamed wood . .■ .. . . .44 

Microscopical examination of steamed wood; Preparation of mechanical 
wood-pulp by the crushing process; Chopping machines, described and 
illustrated ............ 45 

Reduction of the small pieces of wood in a stamping mill; Usual mode of 
working the mass obtained from steamed wood . . . ... 47 

Difference between ground wood and the original material . . .48 

III. 

Preparation of Cellulose from Wood. ( Wood-Celltjlose, Cellulose 
IN THE Technical Sense of the Word, Chemical Wood-Pulp. ) 

Constitution of paper; Principal point in the preparation of cellulose from 
wood 50 

Principal processes employed for the preparation of wood-cellulose; 
Bachet and Machard's method ........ 51 

Preparation of cellulose by means of soda; First step in the manufacture; 
Disintegration of the encrusting substance ...... 52, 

Substitution of sodium sulphite for a portion of the caustic soda; Boiling 
the chips of wood . . 53 

Sinclair's boiler, described and illustrated 54 

lingerer's boiling process ......... 55 

Keegan's process ........... 56 

Use of a battery for lixiviation; Contrivances for washing cellulose. . 57 

Preparation of cellulose by means of sodium sulphite; Further working 
of the washed cellulose ......... 58 

Consumption of wood and chemicals; Yield of finished cellulose from 
various kinds of wood; Preparation of cellulose with the assistance of 
sulphites (sulphite-cellulose according to Mitscherlich's process); Im- 
portance of an abundance of water; Quantity of water required . . 59 

Preparation of the wood; Freeing the trunks from bark; Reduction of the 
wood; Woods most suitable for the preparation of sulphite cellulose . 60 

Operations into which the preparation of cellulose by the sulphite process 
may be divided; Preparation of the sulphite solution according to 
Mitscherlich's process 61 

Limestone for the preparation of the lye; Preparation of the sulphurous 
acid; Tests as to whether combustion of the sulphur is complete . . 62 

The absorbing tower and its arrangement, described and illustrated . . 63 



X CONTENTS. 

PAGE 

Arrangement of a plant .......... 65 

Lye reservoirs; Causes of irregularities in the operation, and their 

remedies ............ 66 

Boiling the wood with the lye; Boiler for this purpose, described and 

illustrated; Brick work for lining the boiler, described and illustrated. 67 
Mode of heating the mass in the boiler; Proportion between wood and 

lye ............. 68 

Test for ascertaining how much effective calcium bisulphite is still present. 69 
Recovery of sulphurous acid; Washing the cellulose. . . . .70 

Freeing the cellulose from admixtures; Arrangement of a stamping mill 

for this purpose ........... 71 

Defects of cellulose and their remedies; Cause of yellowish or brownish 

color; Occurrence of white pieces not converted into fibre; Occurrence 

of black particles and of larger brown bundles of fibre . . . .72 
Change in color of the cellulose during washing; Preparation of cellulose 

with the assistance of the electric current — Kellner's process . . 73 
Apparatus used for this purpose, described and illustrated . . .74 
Advantages of the electrical process; Preparation of cellulose from straw; 

Preparatory operations. ......... 7-5 

Cutting and winnowing the straw; Further working of the winnowed 

straw; Boilers for working the straw ....... 76 

Bleaching the cellulose; Yield of cellulose; Various plants which are 

utilized for the preparation of cellulose . . . . . .77 

Utilization of jute bagging; Mode of working jute; Utilization of exhausted 

lyes and their neutralization ........ 78 

Recovery of soda; Discharge of lyes into running water when working 

with the sulphite process; Dilution of the lyes . . . . .79 
Neutralization of the lyes; A. Frank's process; Utilization of sulphite lyes 

in tanning ............ 80 

IV. 

Vegetable Parchment. 

Change in unsized paper when subjected to the action of sulphuric acid; 
Chemical composition of vegetable parchment; Explanation of the 
parchmentizing action of sulphuric acid ...... 82 

Nature of the paper to be parchmentized; Paper suitable for parchmentiz- 
ing; Preparation of parchment of greater thickness . . . .83 

Sulphuric acid used for parchmentizing; Use of so-called chamber acid . 84 

Time required for parchmentizing; Parchmentizing apparatus . . .85 

Removal of the last traces of acid adhering to the paper; Drying the fin- 
ished parchment; Recovery of the sulphuric acid . . . . .86 

Properties of parchment; Table showing the changes paper undergoes by 
parchmentizing ........... 87 

Preparation of parchment of special thickness; Rendering parchment 
paper flexible .88 



CONTENTS. XI 

PAGE 

Coloring parchment'[paper; Preparation of chrome glue for joining to- 
gether parchment paper ^2 .-...•••• 89 

Applications of vegetable parchment; Vulcanized cellulose (vulcanized 
fibre) , and its preparation; Process according to the patent specification. 90 

Forms in which vulcanized fibre is found in commerce . . . • 91 

V. 

Production op Sugar and AlcohoI/ from WooD-CEiiLULOSE. 

First experiments for the conversion of cellulose into sugar . . .93 

Older methods; Zetterlund's process 94 

Bachet and Machard's process ........ 95 

Other methods for the production of alcohol from wood; Failure of an ex- 
periment for the production of alcohol from beech; Nature of the wood 
to be worked . . . . . . • . . . . .96 

Varieties of wood suitable for the production of alcohol; Apparatus to be 
used and mode of procedure in general ...... 97 

More modern methods for the production of alcohol from wood; Cutting 
up the wood; Conversion of the cellulose into sugar; Boiling under 
pressure ............ 98 

Apparatus used for boiling; Tests as regards the time required for obtain- 
ing the largest possible quantity of sugar ...... 99 

Removal of the hydrochloric acid; Neutralization of the sugar solution . 100 
Fermentation of the sugar solution; Distillation of the fermented fluid . 101 
Value of alcohol obtained from wood; Classen's process for the production 

of directly fermentable sugar from wood ...... 102 

A noteworthy process also patented by Classen. . . . . .104 

Main point of the process ...... ... 105 

Disintegration of the wood by means of chlorine or hypochlorides; An- 
other process patented by Classen. ....... 106 

Modification of Classen' s process ........ 107 

VI. 

Preparation of Oxalic Acid from Wood-Cellulose. 

Materials from which the largest^yields of oxalic acid are obtained; Suita- 
bility of wood for the preparation of oxalic acid ..... 108 

Mode of formation of oxalic acid; Thorn's investigations; Yield of oxalic 
acid from sawdust . . . . . . • • • .109 

Table showing yield of oxalic acid under different conditions; Changes 
taking place in sawdust by treating it with mixtures of caustic alkalies. 110 

Best proportions between caustic soda and caustic potash; Advantage of 
heating the mixture of sawdust and caustic alkalies in a thin layer . Ill 

Prevention of the turbulent reaction during fusion; Capitaines and Hert- 
lings's process 112 



Xll CONTENTS. 

PAGE 

Preparation of oxalic acid on a large scale; Preparation of the mixed lyes; 
Melting apparatus . . . . . . . • • • .113 

Mode of heating; Contrivance for turning the mass while being heated . 114 

Working up the melt; Utilization of the mother-lye 115 

Mode of obtaining pure oxalic acid from the crude sodium oxalate . .116 
Production of pure oxalic acid; Pans used for this purpose . . . 117 
Production of an almost chemically pure product 118 

VII. 

Viscose and Viscoid. 

Invention of these products, in 1892, by Brown, Beadle and Cross; Main 
point of the invention; Regulation of the progress of the conversion of 
viscose into viscoid .......... 119 

Raw material for the preparation of viscose solution; Preparation of vis- 
cose for experimental purposes, and for working on a small scale. . 120 
Preparation of viscose on a large scale; Material for this purpose . . 121 
Comminution of the cellulose, and apparatus used; Quantitative propor- 
tions between cellulose and caustic soda; Recognition of the commence- 
ment of the formation of soda-cellulose. . . . . . .122 

Methods used in practice for the preparation of soda-cellulose. . . 123 
Soda-cellulose; Main point in the manufacture of soda-cellulose; Storing 
of soda-cellulose ........... 124 

Injurious changes in soda-cellulose; Advantages of storing this material in 
an ice-house. . . . . . . . . . . .125 

Products formed by the decomposition of soda-cellulose; Preparation of 
viscose; Properties of carbon disulphide ...... 126 

Apparatus for the preparation of larger quantities of viscose; Proportion 
between soda-lye and carbon disulphide; Nature of cellulose sulphocar- 

bonate 127 

Recovery of carbon disulphide; Preparation of viscose solution . .128 
Storing viscose; Vessels used for this purpose; Stability of viscose; Best 
temperature for preserving viscose . . . . . . .129 

Shipping of viscose; Properties of viscose solutions; Recognition of the 
commencement of the decomposition of a viscose solution; Changes 
taking place in viscose solution ........ 130 

Influence of temperature upon the decomposition of viscose . . . 131 
Conversion of viscose into viscoid; Chief uses of viscose; Preparation of 

thicker plates from viscoid ........ 132 

Behavior of viscose towards metallic salts; Magnesium-viscose. . . 133 
Proportional quantities of bodies added to soda-viscose for the purpose of 
obtaining other varieties of viscose; Preparation of viscose according to 

Cross 134 

Preparation of viscose according to Seidel 135 

Transparent plates from viscose 136 

Mode of giving a loosely- woven, thin tissue the appearance of a close and 
firm fabric . . . . . . . . . . . . 137 



CONTENTS, Xlll 

PAGE 

Preparation of chemically-pure cellulose sulphocarbonate (viscose); Uses 
of viscose; Incorporation of pulverulent substances . -a^^ • • 138 

Use of viscose in the manufacture of paper; Ammonium viscose . . 139 

Advantages of the use of ammonium or magnesium viscose; Application 
of viscose as a size to wi'apping paper; Table showing how the qualities 
of the papers are effected by the addition of viscose .... 140 

Viscose in the manufacture of wall paper; Advantage of its use in the 
manufacture of flock paper; Coating of ordinary wall paper with viscose; 
Imitations of leather and velvet hangings 141 

Viscose in cloth printing; White design upon a colored ground . . 142 

Printing color prepared with viscose; Viscose solution for marking fabrics 
in mills, and as a substitute for ink for marking household linen, etc.; 
Viscose as a size or dressing. ........ 143 

Simplest mode of sizing; Addition of loading agents to the viscose; Im- 
parting smoothness and lustre to the tissue treated with viscose . . 144 

Preparation of leather-like bodies by means of viscose; Constitution of 
leather; Main point in the production of a satisfactory imitation of 
leather 145 

Fabrics to be used and working them up into leather-like masses; Viscose 
solution for impregnating the tissues ....... 146 

First step in the operation; Coloring imitations of leather; Vat for the 
viscose solution; Passing the fabric through the viscose solution . . 147 

Conversion of the viscose into viscoid; Protection of the workmen from 
the gases evolved; Recovery of the carbon disulphide; Finishing and 
drying the fabrics. . . . . . • • • • .148 

Working thick fabrics; Condition of the impregnated fabrics; Properties 
of the impregnated fabrics ......... 149 

Uses of fabrics impregnated with cellulose; Impregnation of ordinary 
pasteboard with viscose solution ........ 150 

Uses of such pasteboard; Felt-plates impregnated with viscose solution, 
and their use ........... 151 

Viscose in the manufacture of artificial flowers; Mode of application; Pure 
viscose for especially delicate flowers ....... 152 

Viscose in photography; Preparation of films from viscose . . . 153 

Viscoid masses; Preparation of homogeneous viscose masses free from 
bubbles 154 

Working of pure viscoid; Incorporation of foreign bodies with the viscose; 
Materials for the preparation of white masses; Masses of a pure, milk- 
white color and of comparatively slight specific gravity . . .155 

Experiment on a small scale in mixing filling substances with viscose . 156 

Properties of a viscoid mass of the proper quality; Preparation of larger 
quantities of viscoid masses; Mixing or kneading machine . . . 157 

Shape of a kneading and mixing paddle, described and illustrated ; Mode 
of working the viscose solution in the mixing machine. . . . 158 

Moulding the viscoid mass, and moulds used for the purpose; Moulding 
solid and hollow articles; Finishing and painting the articles . . 159 



Xiv CONTENTS. 



PAGE 



Viscoid masses with cellulose or mechanical wood pulp as filling sub- 
stances and their various applications 160 

VIIL 

Nitbo-Celi.txlose (Gtjn-Cotton, Pyroxylin). 

Combinations formed by bringing pure cellulose in contact with nitric 
acid; Two distinctly marked groups of combinations; Discovery of the 
combinations formed by the action of nitric acid upon cellulose; Former 
opinions regarding the formation and composition of the combinations. 161 

Modern views i-egarding the composition of gun-cotton; Formation of 
nitro-cellulose . . . . . • . . . . .162 

Preparation of nitro-cellulose in explosive as well as soluble form; Investi- 
gations by G. Lunge and E. Weintraub 163 

Effect of the presence of a very large quantity of sulphuric acid; Use of a 
nitrating fluid containing but a small quantity of sulphuric acid; Time 
required for the completion of the process of nitration .... 164 

Loss in cellulose when working with a nitrating fluid heated to different 
degrees of temperature; Change in the structure of the nitro-cellulose; 
Action of nitro-cellulose towards polarized light 16& 

Main objects to be attained in practice in the preparation of nitro- 
cellulose; Products which come chiefly into question for practical pur- 
poses ............. 166- 

Modes of calculating the nitrogen in nitro-cellulose adopted by the French 
chemists and by the English and German chemists; G. Lunge and J. 
Bebie's investigations; Table showing the relation between the modes 
of determination adopted by the French and German chemists . . 167 

Table showing the influence exerted by the content of water in the acid 
mixture upon the process of nitration ....... 168 

Typical soluble nitro-cellulose — the actual collodion-cotton; Solubility of 
nitro-celluloses 169^ 

Table showing the efiect of higher tempei-atures such as are used in the 
preparation of collodion-cottons . . . . . . . .170 

General use of a mixture of nitric and sulphuric acids for the preparation 
of collodion-cotton; Figures obtained with the use of 1 nitric acid to 3 
sulphuric acid ........... 171 

Nitrating fluids used in the experiments; Table showing the final results 
of further experiments. ......... 172 

Importance of paying attention to the content of water in the nitrating 
fluid; Experiments in this direction ....... 173- 

Analyses of various nitro-celluloses; Preparation of gun-cotton; First 
requisite for the production of gun-cotton ; Purification of raw cotton . 174 

Acid used for nitration; Use of mixtures of concentrated nitric and sul- 
phuric acids; Former mode of nitration; Strength of nitric acid for very 
explosive products and for readily soluble products . . . . 175 



CONTENTS. XV 

PAGE 

Sulphuric acid for nitration; Storage of the acids; Stoneware vessels forlj:^ 
nitrating purposes; Constitution of the nitrating fluid .... 176 

Proportions of acids for explosive gun-cotton and for soluble gun-cotton 
or collodion-cotton; Condition of the nitrating fluid; Importance of the 
constancy of the composition of the acid mixture . • • . . 177 

Regeneration of the nitrating fluids; Use of fuming sulphuric acid; Execu- 
tion of nitration 178 

Nitrating apparatus, described and illustrated. . • . . . 179 

Proportion between acid and cotton; Time required for nitration; Use of 
a centrifugal apparatus for effecting nitration » , , , * 181 

Washing the gun-cotton; Ignition of gun-cotton when introduced into the 
washing tank; Construction of the wash-tank ..... 183 

Changes in gun-cotton ; Measures to insure the removal of the acid, and 
comminution of the gun-cotton for this purpose; Apparatus used . . 184 

Separation of the comminuted gun-cotton from the water , , . 185 

Drying the gun-cotton; Drying upon frames covered with linen; Gutt- 
mann's plan of drying gun-cotton; Mode of heating the drying room . 186 

Hygroscopicity of dry gun-cotton; Mode of packing gun-cotton; Explosive 
gun-cotton, and mode of compressing it 187 

Compression of gun-cotton for loading torpedoes; Increasing the stability 
of the nitro -cellulose; Manifestation of changes in the product . . 188 

A. Luck and C. F. Gross's process for increasing the stability of nitro- 
cellulose; O. E. Schulz's process for this purpose . .... 189 

Soluble gun-cotton or collodion-cotton; Great importance of collodion- 
cotton for the preparation of threads ....... 190 

Influence of the duration of the action of the acid mixture upon the cot- 
ton; Temperature to be used for nitration; Connection between the solu- 
bility of nitro-celluloses and the content of nitrogen in the products . 191 

Characteristics of properly prepared collodion-cotton; Disintegration of 
the nitro-combination; Collodion-cotton from fine tissue-paper , . 192 

Collodion; Collodion for photographic purposes; Material best adapted 
for the preparation of collodion ........ 193 

Composition of nitro-celluloses; Cellulose hexanitrate; Cellulose tetra- 
nitrate ............. 194 

Cellulose trinitrate; Cellulose dinitrate; Behavior in drying of a solution 
of dinitro-cellulose in ether-alcohol; Effect of an admixture of dinitro- 
cellulose upon collodion . ... ... ... 195 

Neutralization of the collodion-cotton; Preparation of the solution; Influ- 
ence of the physical condition of collodion-cotton upon its solubility; 
Mode of keeping collodion-solution . . . . . , .196 

Elastic masses from nitro-cellulose (artificial rubber); Production of 
masses from nitro-cellulose possessing considerable elasticity; Fluids 
which may be used for this purpose 197 

Mechanical manipulation of the mass; Most suitable solvent; Recovery of 
the volatile solvent; Further manipulation of the mass. . • . 198 

Nature of the masses finally obtained; Mixing the masses with indifferent 
bodies; Inflammability of the masses and mode of reducing it . . 199 



Xvi CONTENTS. 

PAGE 

Cellulose esters; Cellulose acetic ester 200 

Composition of cellulose tetra-acetate, and its indifFerence towards the 

action of chemicals .......... 201 

Applications of cellulose acetic ester; Preparation of an acetyl derivative 

of cellulose according to L. Lederer ....... 202 

Cellulose butyric ester; Other similar combinations; "Solid spirit;" Mode 

of bringing alcohol into a solid form ....... 203 

IX. 

Artificial Silk. 
Source of natural silk; Composition of raw silk; Scouring or boiling raw 

silk ; ; ; ; 205 

Appearance of silk under the microscope; Early efforts to produce artifi- 
cial silk; Varieties of artificial silk 206 

Historical development of the artificial -si Ik industry; Credit due to M. de 
Chardonnet; Du Vivier's and Lehner's processes; A. Millar's method; 
Hummel's process .......... 207 

Cadoret's method; Diiference between the methods according to which 
textile threads are prepared from pure cellulose and from nitro-cellu- 
lose; Invention of Dr. Hermann Pauldy; Process proposed by Langhaus. 208 

Cheapness and safety of the preparation of silk-like threads from viscose 
solution; Chardonnet artificial silk; Chardonnet's original patent for 
preparing textile threads 209 

Details of the practical application of Chardonnet's process; Nitration of 
the cotton 210 

Nitrating vessels; Time required for nitration ...... 211 

Physical behavior of the nitrated cotton; Physical examination of the 
nitrated cotton; Results of Chardonnet' s comparative experiments . 212 

Eemoval of acid from the cotton; Washing the nitrated cotton; Prepara- 
tion of the collodion solution ........ 213 

Solvent used; Time required for solution; Filtering the solution and filter 
for the purpose 214 

Storing the solution; Spinning the collodion; Disposition of the spinning 
apparatus; Mode of making the glass spinners 215 

Arrangement of the spinners; Reeling up the threads; Removal of the 
vapors of alcohol and ether from the spinning room .... 216 

Chardonnet's spinning apparatus, described and illustrated . . . 217 

Condensing vessels; Throwing or twisting the individual threads; Inflam- 
mability of artificial silk; Denitration ....... 219 

Mode of effecting denitration; Composition of denitrating fluids; Use of 
ammonium sulphide for the purpose, and its preparation; Recognition 
of the correct composition of the denitrating fluid .... 220 

Bleaching the silk; Preparation of colored artificial silk; Direct coloring 
of the silk while in the course of preparation; Mixture of the coloring 
matter with the collodion . . . . . . . • . 221 



CONTENTS. XVll 

PAGE 

Dyeing the finished silk; Du Vivier's artificial silk .... 222 

Method of nitration by means of dry saltpetre and sulphuric acid; Solvent 

for the nitro-cellulose .......... 223 

Lehner's artificial silk; Solvent for the nitro-cellulose; Modification of 

Lehner's process ........... 224 

Denitration of artificial silk; H. Richter's investigations regarding this 

subject; Pith of Richter's method; Cuprous chloride for denitration . 225 
Special advantage claimed for Richter's process; Recovery of the nitrogen 

compounds; Recovery of the oxy-salts 226 

A. Peit's method for the preparation of artificial silk; Drawbacks of the 

process of producing artificial silk from nitro-cellulose; Spontaneous 

ignition of nitro-cellulose ......... 227 

X. 

Cellulose Threads (Cellulose Artificial Silk and Lustra- 
Cellulose). 

Methods for the conversion of cellulose into a solution from which 
artificial textile threads may be produced; Advantages of the process; 
Use of cuprammonium as solvent for cellulose ..... 229 

Dr. Pauly's artificial silk; Operation for the production of the thread; 
Purification of the cotton ......... 230 

Dissolving the cotton in cuprammonium; Apparatus for the purpose . 231 

Judging the progress of solution by samples ...... 232 

Filtration of the solution and filter used for the purpose .... 233 

Spinning the solution; Construction of the contrivance in which the 
formation of threads is effected; Arrangement of the spinners; Col- 
lector for the threads .......... 234 

Washing the threads; Further manipulation of the threads by mechani- 
cal means; Properties of cellulose artificial silk ..... 235 

E. Bronnert's process for the preparation of textile threads; Conversion 
of cellulose into soda-cellulose; Use of the substances according to 
molecular weights .......... 236 

Preparation of cuprammonium; Removing the turbidity of the solution; 
Filtering the solution .......... 237 

Conversion of cupric hydroxide into cuprammonium, and apparatus 
employed ............ 238 

Preparation of cuprammonium solution according to the process of E. 
Bronnert, M. Fremery and J. Urban 239 

Recovery of the copper; Various methods for this purpose . . . 240 

Artificial silk according to M. Fremery and J. Urban; Manner of drying 
the thread ; Phases in the drying process 242 

Composition of the fluid used for the decomposition of the cellulose solu- 
tion; Explanation of the effect of concentrated sulphuric acid . . 243 

Artificial horse hair, its production and uses ...... 244 



XV 111 CONTENTS. 



XL 



Textile Threads prom Viscose (Threads from Lustra-Celllulose). 
Coagulation of viscose solution; Simplicity of the process of obtaining pure 
cellulose from viscose; Experiments in making textile threads from 
viscose. ............ 246 

Properties of viscose threads; Cost of producing threads from viscose . 247 
Preparation of perfectly clear viscose solution, and apparatus employed . 248 
Filtering the solution, and filter used; Spinning apparatus . . . 249 
Treatment of the threads emerging from the spinning apparatus . . 250 
Importance of using viscose solution of the same temperature . . . 251 
Kegulation of heat; Preparation of textile threads according to Stearn.; 
Preparation of long, narrow strips for taking pictures for the cinemato- 
graph 252 

Millai-'s artificial silk (gelatine silk) . . . . . . .253 

Deprivinggelatine threads of their brittleness; General properties of textile 
threads produced by artificial means; Lustre of artificial silk; Effect of 

water on artificial threads 254 

Facts to be taken into consideration in dyeing threads of artificial silk; 
Microscopical examination of artificial textile threads; Difference be- 
tween natural and artificial silks ........ 255 

Table showing diameters of various kinds of silks; Optical phenomena ex- 
hibited by natural and artificial silks; Tenacity of artificial silk as com- 
pared with natural silk 256 

Dr. Hassack's investigations; Moisture and hygroscopic! ty of artificial 

silks; Specific gravity of artificial silks 257 

Elasticity and tenacity of artificial silk; Eesults of tests .... 258 
Behavior of artificial silk in a chemical respect; Principal difference be- 
tween the various kinds of artificial silk 259 

Microscopical examination of artificial silk with the use of reagents. . 260 
Distinction between cellulose and nitro-cellulose silks .... 261 

XII. 

Celluloid. 
Invention of celluloid by Hyatt, of Newark, N. J. ; Properties of cellu- 
loid; Nature of celluloid 263 

Methods for the preparation of celluloid; Value of the separate methods . 264 
Classification of the methods used for the manufacture of celluloid; Prep- 
aration of the collodion-cotton 265 

Material used according to the original statements by Hyatt; Preparation 

of celluloid according to Hyatt 266 

Preparation of celluloid according to Tribouillet and Besancele . . 268 
Preparation of celluloid with alcoholic camphor solution .... 269 

Preparation of celluloid according to Magnus 270 

Mode of preparing the solution of dry collodion-cotton; Preparation of 



CONTENTS. XIX 

PAGE 

celluloid with recovery of the solvent; Description of a process which 
can be practically applied ......... 271 

Manner of testing freshly-prepared collodion-cotton; Requisites of collod- 
ion-cotton which is to be dissolved ....... 272 

Drying the collodion-cotton; Apparatus in which the solution of collod- 
ion-cotton and camphor is effected, and manner of working with it; 
Solvent to be used .......... 273 

Advantages of anhydrous ether as a solvent; Recovery of the ether 
evaporating from the fluid celluloid mass ...... 274 

Apparatus for preparing the solution ; Trays for solidifying the solution, 
described and illustrated ......... 275 

Apparatus for condensing the ether-vapors, described and illustrated . 276 
Removing the finished celluloid from the trays ..... 278 

Drying chamber; Heating celluloid to be rolled ..... 279 

Properties of celluloid; Nature of celluloid at the ordinary temperature . 280 
Mode of rendering celluloid plastic by heating; Spontaneous decomposi- 
tion of celluloid; Inflammability of celluloid. ..... 281 

Behavior of celluloid towards solvents; Physical properties of celluloid; 

Example of the great tenacity and elasticity of celluloid . . . 282 
Working celluloid; Mechanical manipulation of celluloid; Rolling cellu- 
loid 283 

•Coloring celluloid; Employment of tar colors for this purpose; Coloring 
transparent celluloid articles; Production of articles from the colored 
material ............ 284 

Production of certain color effects; Red and scarlet ..... 285 

Blue; Indigo-blue; Berlin-blue; Violet; Brown; Gray; Black . . . 286 
Printing on celluloid; Preparation of a celluloid-plate for printing; Pro- 
cess for providing celluloid articles with colored pictures . . . 287 
Transferring pictures to celluloid; Mode of protecting the pictures . . 288 
Printing on celluloid in the same manner as pictures, in many colors, are 
produced on paper; Preparation of gutta-percha printing blocks; Cellu- 
loid with filling masses. ......... 289 

Milk-white bodies; Imitation of white marble; Materials used; Celluloid 
masses of light weight .......... 290 

Methods for combining the pulverulent filling substance with the cellu- 
loid; Coloring filled celluloid masses; Imitation, of ivory . . . 291 
Imitation of tortoise-shell ......... 292 

Moulding celluloid articles; Heating apparatus for the purpose, described 
and illustrated ........... 293 

Manufacture of celluloid tubes; Joining two pieces of celluloid. . . 294 
Shaping celluloid by pressing; Imitations of corals; Manufacture of 
combs; Cliches from celluloid ........ 295 

Method of making a plaster of Paris cast; Celluloid stamps . . . 296 
Collars and cuffs from celluloid; White masses for this purpose; Making 
the mould; Cleaning celluloid collars and cuffs ..... 297 

-Celluloid for dentists' use . . . 298 



XX CONTENTS. 

PAGE 

Coloring celluloid with cinnabar; Mode of making the plates; Temijera- 
ture to which the celluloid has to be heated 299 

Objects of art from celluloid; Metals used for incrustations; Finishing the 
incrusted plate; Bending incrusted plates 300 

Celluloid mosaics; Imitation of lapis lazuli^ and of variegated marble; Pro- 
duction of mosaics; Execution of the design 301 

Celluloid lacquer; Use of celluloid lacquer for coating maps, copper and 
steel engravings and drawings ........ 302 

Protecting metals from rust; Basis-material of all celluloid lacquers; Names 
under which celluloid lacquers are brought into commerce . . . 303 

Preparation of an excellent celluloid lacquer 304 

Effects produced with colored celluloid lacquers; Conservation of metals 
by means of celluloid lacquer; Special importance of a coating of cellu- 
loid lacquer for metallic articles which come in contact with sea water. 305 

Protection of iron vessels from the action of sea water; Celluloid masses 
without an addition of camphor; Use of naphthaline .... 306 

Substitutes for camphor proposed by Zuhl and Eisemann, and by J. E. 
Goldsmith 307 

XIII. 

Rtxbbek Compounds. 
Definition of rubber compounds; Principal substances used as additions to 

rubber 309 

Advantages of coal-tar pitch; Plastite masses, and their nature . . 310 
Composition of plastite masses, and their preparation; Elastic rubber 
masses ............. 311 

Balenite, its composition and preparation; Uses of balenite; Rubber- 
leather; Properties and preparation of rubber-leather . . . .312 

Cost of producing i-ubber-leather; Marine glue, and definition of this term. 313 
Mode of applying marine glue; Preparation of a lacquer from marine glue. 314 

XIV. 

RtTBBER Substitutes. 
Increasing demand for rubber; Groups of rubber substitutes; Steenstrup's 

method for -the preparation of a rubber substitute 315 

Importance of actual rubber substitutes, and their preparation by the 

treatment of oils; Oil-rubber; Drying and non-drying oils; First step 
in the manufacture of oil-rubber . . . . . . . 316 

Heating the oil;^Test as to whether the oil has been suflSciently heated; 

Cooling the oil . . . . . . . . . . .317 

Oxidation of the oil with nitric acid; Nature of the oil-rubber obtained . 318 
Restoring old oil-rubber; Uses of oil-rubber; Manufacture on a large 

scale of oil-rubber by means of thick oil ..... . 319 

Apparatus for oxidizing the oil, described and illustrated . . . 320 



CONTENTS. XXI 

PAGE 

Time required for thickening the oil; Working the thick oil . . . 321 
Use of oil-rubber for securing large panes of glass in frames; Factis 

masses, and their nature ......... 322 

Sulphured oils (brown and black factis) and their preparation . . 323 

Substances which may be added to oil-rubber; Vulcanized oil, and its 

preparation ............ 324 

White factis; R. Henriquez's investigations ...... 325 

Oils used for the production of factis, and quantities of disulphur dichlor- 

ide required for their manipulation ....... 326 

Vessels for the oxidation of the oils; Boilers for the preparation of factis. 327 
Mode of mixing factis with genuine rubber; Sulphuretted hydro-cellulose 

as rubber substitute, and its preparation according to Sthamer . . 328 
Preparation of disulphur dichloride, and apparatus used, described and 

illustrated 329 

Preparation of pure disulphur dichloride for experimental purposes . 330 
Necessity of exercising care in handling disulphur dichloride . . . 331 
Index 333 



CELLULOSE, CELLULOSE PRODUCTS, 
AND RUBBER SUBSTITUTES. 



I. 

CELLULOSE. 



The substance to which the term cellulose has been 
applied is very widely distributed throughout nature, it 
forming the structural basis of all vegetable organisms. 
All plants, from the unicellular bacterium up to the mam- 
moth conifers of California, are built up of cells, the en- 
velopes or walls of which consist, in every case, of one and 
the same body, namely, cellulose. In the higher plants 
the individual contiguous cells coalesce in such a way that, 
in certain places, their walls are broken up, tubular struct- 
ures — the so-called vessels — which frequently attain extra- 
ordinary lengths, being thereby formed. There are vessels 
which extend from the roots to the tops of gigantic trees, 
and, as above stated, have been formed by the coalescence 
of individual cells of a more or less globular form. 

While in many plants the cells, as well as the vessels 
formed from them, always remain soft, in others combina- 
tions are deposited in them by which the cellulose is 
•changed in a characteristic manner, the walls of the vessels 
frequently acquiring considerable firmness ; and the cellu- 
lose vessels are changed to wood-vessels. In herbaceous 
plants such a transformation does not take place, and 
hence they have to be sharply distinguished from the 



2 CELLULOSE, AND CELLULOSE PRODUCTS. 

< 

wood-forming plants, and the process of the formation of 
wood will have to be more closely discussed. 

OCCURRENCE OF CELLULOSE. 

While formerly the opinion prevailed that cellulose oc- 
curs exclusively in the vegetable organism, more recent 
investigations have also shown its presence, though to a 
limited extent, in the animal kingdom, its occurrence in 
many Tunicata having been definitely established, and it 
has also been found in insects and other articulates. Its 
occurrence in the skins of snakes has not been finally 
proved. It is also claimed that cellulose is formed in the 
human organism during certain morbid processes (tubercu- 
losis). However, such occurrences are of minor importance, 
all the cellulose made use of being exclusively derived from 
plants. Formerly we had to content ourselves with such 
quantities of cellulose as were in a quite pure state at our 
disposal in the form of vegetable wool and the fibres of 
textile plants, but the demand for cellulose having ac- 
quired colossal dimensions by reason of the enormous in- 
crease in the consumption of paper, efforts had to be made 
to open up other sources of it. 

Attention was first directed towards straw as a material 
for the preparation of cellulose, because it was supposed that 
its vessels having been only slightly, or not at all, converted 
into wood, the cellulose could without much difficulty be 
obtained in a sufficiently pure state. However, it was left 
out of consideration that the stalks of grasses, which in a 
dry state form the material termed straw, contain consider- 
able quantities of silica and, in many cases, are provided 
with what may be called a siliceous armor. This fact 
frustrated for a long time every attempt to prepare from 
straw cellulose which might at least be available for the 
manufacture of paper. Although successful processes for 
the treatment of straw for paper-making were finally intro- 
duced, the pulp obtained as well as the papers manufac- 



CELLULOSE. 6 

tured from it, showed so many defects that this mode of 
obtaining cellulose was soon again abandoned. 

The employment of wood for the successful preparation 
of cellulose in a pure state, and in any quantities desired, is 
an achievement of modern times, no attempt having been 
formerly made to utilize this material for the purpose. 
Chemically, wood is nothing but cellulose which has under- 
gone certain changes. Originally, every kind of wood is 
cellulose, and in genuine woody plants there is always 
found around the stalk a growing annular layer which, in 
accordance with its nature, has to be designated as cellu- 
lose. This annular layer, to which the term liber has been 
applied, is formed anew in every period of vegetation, and 
in the next and succeeding periods of vegetation it is grad- 
ually transformed into wood. 

This transformation is efifected by various bodies, known 
by the general term of encrusting substances, becoming im- 
bedded in the cellulose mass. By this encrustation the 
originally thin walls of the vessels of which the liber con- 
sists, become thicker, more solid, acquire a dark coloration, 
and are finally transformed into wood-vessels of consider- 
able strength and tenacity, extraordinarily great in some 
varieties of wood. 

The encrusting substances of the wood possess the prop- 
erty of being destroyed or dissolved by various chemicals, 
while the cellulose is not at all, or but slightly, attacked by 
them. Hence by one or the other of the processes to be 
fully described later on, a cellulose is obtained which, when 
sufficient care has been taken in purifying it, may be called 
chemically pure, i. e., free from all foreign bodies. 

COTTON. 

Cellulose as found in nature is never chemically pure, it 
containing in addition a series of other combinations. In 
its purest state it occurs in the vegetable structures known 
as hair or wool. As a rule, each hair consists of a mem- 



CELLULOSK, AND CELLULOSE PRODUCTS. 



Fig. 1. 



branous cell, frequently of considerable length, the wall of 
which is formed of cellulose, admixed, however, with certain 
salts, nitrogenous combinations, and, in some cases, with 
coloring matter. 

Cotton is, unquestionably, the most important of all the 
vegetable wools. It is the product of several species of the 
genus Gossypium of the Natural Order Malvacex or Mallows. 
The cotton plant has from time immemorial been cultivated 
in tropical countries. The cotton is found in the fruit of 
the plant, and actually is the hairs or fibres growing around 
the seed and attached to it. This attachment of the hairs or 
fibres to the seed is typical of the genus. The fruit. Fig. 1, 
known as boll, consists of a capsule or pod divided by mem- 
branes into three or five cells. It bursts at the time of 
maturity and the hairs or fibres protrude from it in the form 
of a compact ball of a white or yellow color. The seeds are 
the size of a pea and the cotton 
fibres are separated from them by 
means of special mechanical con- 
trivances. 

Viewed under the microscope, the 
cotton fibre appears as a hollow 
cylinder, one end of which is pointed 
and closed, while the other end, by 
means of which it was attached to 
the seed, is irregularly torn. Cotton 
is the more highly valued the thin- 
ner the individual fibres are, the 
more uniformly smooth they appear 
under the microscope, and the more 
closely their form approaches that 
of a cylinder. Fig. 2 shows cotton 
fibres highly magnified. As will 
be seen from the illustration, the individual fibres are more 
or less strongly twisted and smooth, but with the use of a 
very high magnifying power they appear obliquely striate. 




Fruit of the Cotton Plant. 



CELLULOSE. O 

The length of the cotton fibre varies between 0.391 and 
1.575 inches, and its diameter between 0.0004 and 0.0016 
inch. In fine qualities of cotton the cavity or lumen of the 
fibre is quite narrow, while in coarser varieties it is three 
or four times the size of the cell-wall ; in unripe fibres it is 
sometimes entirely wanting. Like the striation. of the 
fibre, its cuticle can be plainly recognized only with a very 
high magnifying power. 

Fig. 2. 




Cotton Fibres. 

Ff cotton filaments ; d, places of twist ; g C, granulated cuticle ; I, cavity or 

lumen ; Q, cross sections. 

The value of a variety of cotton is determined by two 
factors, namely, the length and diameter of the individual 
fibres ; the longer the fibres are and at the same time the 
smaller their diameter is, the more valuable the cotton. 
Cotton with fibres less than 0.984 inch long is called short- 
staple as distinguished from long-staple, the fibres of which 
may reach a length of up to 2.362 inches. With regard to 
the diameter of the fibres, eight different grades of fineness 
are distinguished in commerce, the limits of diameter for 
the respective classes being from 0.0004 to 0.0016 inch. 



6 CELLULOSE, AND CELLULOSE PRODUCTS. 

According to numerous analyses, the chemical composi- 
tion of cotton is as follows : Cellulose 87 to 91 per cent., 
water 5.2 to 8.0 per cent., fat and wax 0.4 to 0.5 per cent., 
nitrogenous bodies (remains of protoplasm) 0.5 to 0.7 per 
cent., ash 0.1 to 0.13 per cent. 

In addition to cotton, there are numerous other plants 
producing fibres consisting largely of cellulose, and which 
are also used as textile fibres. Among them may be men- 
tioned the fibres of the various species of Bomhax or wool 
tree, and of the different varieties of Asclepias, but they are 
far behind cotton in technical importance. 

Other natural sources of cellulose-fibres are the bast of a 
large number of plants, and finally the fibres obtained by a 
special process (retting) from the stalks and leaves of many 
plants. As the most important of these may be mentioned : 
flax, hemp, various kinds of nettle, jute, aloe, Manila hemp, 
New Zealand flax, etc. For the purpose of preparing from 
cotton a cellulose which may be considered chemically pure, 
white cotton is first for some time extracted with ether to 
dissolve the entire quantity of fat and wax present. It is 
then repeatedly boiled with soda lye, which, however, 
should not be too concentrated, whereby the nitrogenous 
combinations are brought into solution. Very dilute hy- 
drochloric acid is then poured over the cotton and the 
whole gently heated, the operation being continued for 
some time. Finally the cotton is treated with water till the 
last traces of acid have disappeared. When incinerated, 
cotton, which has been sufiiciently purified, should leave 
no residue. 

PROPERTIES OF CELLULOSE. 

Cellulose, purified in the manner given above, remains 
unchanged as regards its structure, chemicals when used in 
sufficiently dilute state having no effect upon it. The 
elementary analysis of cellulose leads to the formula 
C12H20O10. However, this formula actually expresses 



CELLULOSE. 7 

only its elementary composition, and the actual formula 
would probably correspond to quite considerable multiples 
of the numbers above mentioned. 

As regards the percentage composition, cellulose agrees 
with a very large number of other bodies which frequently 
occur in plants. Thus, it has, for instance, the same com- 
position as starch, gum, gum-like substances, dextrin, etc. 
These bodies form a large group of isomeric combinations, 
they having the same percentage composition, but exhibit- 
ing different physical and chemical properties. 

There can be no doubt that in the living plant-organism 
these bodies may constantly be transformed one into the 
other, incontestable proof of this fact being furnished by 
the bulbs and tubers of many plants. In the cells of such 
bulbs and tubers large quantities of starch are stored up, 
but as the development of the plant progresses, the quan- 
tity of starch decreases more and more, it being largely 
transformed into cellulose, gum, etc. Since cellulose may 
be converted into soluble combinations by the acids formed 
in plants, it would not seem improbable that, in the higher 
plants, the chemical process takes place in such a way that 
a very large number of non-nitrogenous compounds occur- 
ring in plants may be directly or indirectly formed from 
these combinations. 

It would also seem very probable that the acids and fer- 
ments, which appear during the digestion of nutriment in 
the stomach, possess the property of transforming cellulose 
into soluble combinations, because many animals can digest 
considerable quantities of cellulose, it forming a very im- 
portant fodder for them. While formerly the opinion pre- 
vailed that cellulose is absolutely indigestible for carniv- 
orous animals and human beings, recent researches have 
shown such not to be the case and that the human stomach 
is, after all, capable of digesting quite remarkable quanti- 
ties of it. 



8 CELLULOSE, AND CELLULOSE PRODUCTS. 

SOLUBILITY OF CELLULOSE. 

Cellulose is insoluble in ordinary solvents, such as water, 
alcohol, ether, etc., and, without undergoing a change, 
actually dissolves only in amraoniacal solution of cupric 
oxide. When brought in contact with such a solution, the 
fibres first swell up very much, and solution is then grad- 
ually effected. On mixing the solution with alcohol or 
sugar solution, or neutralizing it with an acid, the cellulose 
is precipitated in colorless flakes, retaining, however, its 
original chemical properties. 

Formerly no other solvent for cellulose than ammoniacal 
solution of cupric oxide was known, but towards the end of 
the 19th century a body also capable of dissolving it was 
found in the alkaline sulphocarbonates. Solutions of cellu- 
lose prepared according to this method exhibit peculiar 
properties which will without doubt insure their extensive 
application in various branches of industry. As an exam- 
ple may here be mentioned that textile threads may be pre- 
pared from such a cellulose solution. 

The behavior of cellulose towards the action of chemical 
agents is of great importance since a series of combinations 
of considerable industrial interest may thus be formed. 

BEHAVIOR OP CELLULOSE TOWARDS WATER. 

At the ordinary temperature water has no effect what- 
ever upon cellulose. In boiled water pure cellulose may be 
kept for any length of time without suffering any change. 
If, however, moist cellulose be exposed to the air, the com- 
mencement of a change will in a short time be observed, 
the originally white mass turning gray, becoming constantly 
darker and finally acquiring the appearance of the black- 
brown mould found in the rotten core of trees. A micro- 
scopical examination of such altered cellulose shows it to 
contain innumerable bacteria which, in appearance, closely 
resemble those found in wood mould. This destructive 
process in cellulose is very probably similar to that which 



CELLULOSE. 9 

takes place in the decay of wood, if not entirely identical 
with it. 

That cellulose belongs to the readily changeable com- 
binations is shown by the fact that at a higher temperature 
it is noticeably affected by water. By boiling pure cellu- 
lose with distilled water, for some time in an open vessel 
under the ordinary pressure, a portion of it is converted 
into sugar. In water in which pure filter-paper has been 
boiled, the presence of sugar can be distinctly established. 

The action of water upon cellulose is, however, consider- 
ably enhanced by boiling for a certain length of time under 
increased pressure. With a pressure of 5 to 6 atmospheres 
the cellulose is very noticeably attacked, and the higher 
the pressure becomes the more energetically the water acts 
upon the cellulose ; with a pressure of 20 atmospheres the 
cellulose becomes completely hydrated and is changed to 
hydrocellulose. 

However, at this pressure not only hydration of the cellu- 
lose takes place, but there appear also other products re- 
sembling those which are obtained in abundance in the 
destructive distillation of wood, especially in the first stages 
of it ; the presence of considerable quantities of formic and 
acetic acids having been established in water wdtli which 
cellulose had been treated. In addition, dextrin-like bodies 
are also formed. 

HYDEOCELLULOSE. 

The combination of cellulose with water, called hydro- 
cellulose, has the composition C12II22O11. Hence it differs 
from ordinary cellulose which has the composition 
C12H20O10 ill containing one more equivalent of water. 
For the preparation of pure hydrocellulose use is made of 
the energetic action of highly dilute acids upon cellulose 
even when brought in contact with them at a lower tem- 
perature. On a large scale the mode of manufacture is as 
follows : Mix 3 parts of concentrated sulphuric or hydro- 



10 CELLULOSE, AND CELLULOSE PRODUCTS. 

chloric acid with 97 parts of water, and immerse in the 
fluid purified cotton — entirely free from fat — until it is 
completely saturated, which will be the case in at the 
utmost three to four minutes. The cotton is then taken 
from the mixture and freed as quickly as possible from 
adhering fluid, this being best effected by means of a 
centrifugal apparatus. It is then spread out in a thin layer 
and allowed to dry completely in the air. The air-dry 
mass is finally placed in stoneware vessels and heated for 
three to ten hours at a temperature which should not be 
below 104° F., and not exceed 158° F.; the higher the 
temperature the less time is required for heating. The 
hydrocellulose is then washed with water till the last traces 
of acid have been removed, and is finally completely dried 
in the air. 

Hydrocellulose has the appearance of the cotton from 
which it has been prepared, but can be readily rubbed to a 
very fine powder. It is manufactured on a large scale be- 
cause it possesses the property, when converted into gun- 
cotton, of yielding a product which can be more readily 
exploded by percussion than ordinary gun-cotton, and it is, 
therefore, preferably used for the preparation of detonating 
fuses for military purposes. 

For the preparation of larger quantities of hydrocellulose, 
R. Sthamer uses the following process : Chlorine is con- 
ducted into glacial acetic acid until the latter is perceptibly 
colored yellow. It is then heated to between 140° and 
158° F., and dry cellulose separated into fibres is intro- 
duced while the mass is constantly stirred. The cellulose 
in a short time swells up very much, so that the mass can 
scarcely be stirred, hence three to five parts by weight of 
acetic acid should be used to one part by weight of cellu- 
lose. The mass at first increases constantly in volume, but 
after some time it sinks down, and is finally transformed 
into a thin paste which is washed with water and dried. 
Care must be taken not to allow the temperature to rise 



CELLULOSE. 11 

above 158° F., as otherwise oxidizing processes may take 
place in the mass, and the hydrocellulose would not 
exhibit a pure white, but a brownish color. 

In place of glacial acetic acid, hydrochloric acid, which 
is cheaper, may also be used for the preparation of hydro- 
cellulose, the process, according to Sthamer being as fol- 
lows : Bring into a vessel provided with a steam jacket and 
a stirring apparatus, 200 lbs. of cellulose in fibres and add, 
with constant stirring, 1600 to 2000 lbs. of crude hydro- 
chloric acid of 21° Be., keeping the temperature at 158° F. 
A small quantity of finely pulverized potassium chlorate — 
about 0.5 to 0.8 oz. at a time — is from time to time added 
to the mass. When in the course of about 1^ hours a total 
quantity of 2 lbs. of potassium chlorate has been added, 
the formation of hydrocellulose may be considered finished, 
the end of the reaction being recognized by the uniformly 
pasty nature of the mass. The hydrochloric acid is whirled 
out by means of a centrifugal apparatus, and may be used 
for the next operation. The hydrocellulose is then washed 
and dried. The time required for finishing the process de- 
pends largely on the nature of the cellulose used, a fine- 
fibered material requiring less time than one with close 
and tough fibres. 

Hydrocellulose prepared with the use of potassium 
chlorate is said to be distinguished by very great chemical 
indifference towards acids and lyes, and its use for the 
manufacture of articles which come in (Contact with them is 
especially recommended by Sthamer. 

BEHAVIOR OF CELLULOSE TOWARDS ACIDS. 

While in the presence of even small quantities of acid, 
especially of strong inorganic acids, the action of water 
upon cellulose is very much enhanced, the acids them- 
selves do not enter into combination with the pjoducts 
formed. Hence it may be supposed that by the action of 
the acids upon the cellulose certain combinations are 



12 CELLULOSE, AND CELLULOSE PRODUCTS. 

formed which, however, are again immediately decomposed 
SO tliat the liberated acid can act upon a fresh quantity of 
cellulose. If this supposition is correct, the phenomenon 
of the mere presence of minute quantities of acid being 
suflBcient to change an almost unlimited quantity of cellu- 
lose is readily explained. 

The behavior of cellulose towards acids varies according 
to the kind of acid, its concentration, and duration, of its 
action. Highly diluted sulphuric acid has no effect what- 
ever, even if left for a long time in contact with cellulose, 
but when boiled with it for some time, the cellulose is 
partly transformed into fermentable sugar. Upon this be- 
havior are based various processes for the preparation of 
alcohol from cellulose or wood. The fluid obtained by 
boiling cellulose with dilute sulphuric acid is neutralized 
with lime and brought into alcoholic fermentation with 
yeast. The process has the appearance of being a very 
simple and obvious method of manufacturing alcohol, nev- 
ertheless in practice a number of difficulties are encoun- 
tered, so that hitherto very little use has been made of this 
property of cellulose. 

When cellulose, best in the form of unsized paper, is for 
a few seconds immersed in concentrated sulphuric acid, and 
the acid is then quickly removed by washing in a large 
quantity of water, it undergoes a profound physical change. 
The paper by this treatment acquires great strength, and in 
appearance resembles parchment. By treating paper Avith 
concentrated solution of zinc chloride, a product resembling 
parchment is also obtained. 

Cellulose is completely dissolved if allowed to remain 
for some time in contact with cold concentrated sulphuric 
acid. If, in a short time after solution is complete, the 
fluid be diluted with water, a colorless body having the 
composition of cellulose is separated and which, from its 
resemblance to starch, has been termed amyloid. 

If solution of cellulose in concentrated sulphuric acid be 



CELLULOSE. 13 

allowed to stand for some time, the cellulose is completely 
converted into dextrin. 

However, when boiled with concentrated sulphuric acid, 
cellulose is entirely decomposed, and by reason of its car- 
bonization imparts to the fluid a deep black color. The 
sulphuric acid is also decomposed, as shown by the develop- 
ment of sulphur dioxide from the hot fluid. 

Generally speaking, the action of hydrochloric acid upon 
cellulose is similar to that of sulphuric acid, its effect, how- 
ever, being less energetic, and in boiling cellulose with it 
no carbonization takes place. 

Sulphurous acid acts quite energetically, especially with 
the use of higher pressure, and converts cellulose partially 
into fermentable sugar. 

By organic acids, such as tartaric, citric and acetic acids, 
cellulose is but slightly attacked, they acting somewhat 
more energetically when in a concentrated state; oxalic 
acid produces the most vigorous effect. 

Nitric acid effects profound chemical changes in cellulose, 
the nature of the products formed depending on the con- 
centration of the acid used and the duration of its action. 
Cellulose esters or cellulose nitrates or nitro-cellulose are 
formed, a group of combinations which are especially dis- 
tinguished by their power of exploding with great force 
and dissolving in various bodies. However, notwithstand- 
ing the profound chemical change, nitrated cellulose ex- 
hibits no difference in its physical structure. Under the 
microscope it presents the same appearance as non-nitrated 
cotton, but differs from it essentially in its behavior towards 
polarized light. 

The acid sulphites of the alkalies and alkaline earths 
attack cellulose only to a very limited extent, but they act 
all the more vigorously upon the encrusting substance of 
the wood. The same is the case with free chlorine, and 
the action of the sulphites and of chlorine (the latter in the 
electro-chemical process) is made use of in the preparation 
of cellulose from wood. 



14 CELLULOSE, AND CELLULOSE PRODUCTS. 

Cellulose also forms with a number of organic acids, such 
as acetic acid, butyric acid, etc., combinations which possess 
the characters of esters. These combinations, which have 
only recently been discovered and investigated, show prop- 
erties which lead to the expectation that they may also be 
of industrial importance, though at present they only have 
been experimented with on a small scale. 

BEHAVIOR OF CELLULOSE TOWARDS ALKALIES. 

The caustic alkalies — caustic potash and caustic soda — 
when allowed to act for a short time produce a favorable 
change in cellulose, the fibres becoming more compact and 
solid, so that fibres, especially those of cotton thus treated, 
can be more readily dyed and acquire a more beautiful 
color than the ordinary material. 

When concentrated solutions of caustic alkali — caustic 
potash or caustic soda — are for a short time allowed to act 
upon cellulose (cotton) the fibres undergo a peculiar change. 
Fibres thus treated, when viewed under the microscope, 
appear very much swollen, their cross sections are much 
enlarged and nearly circular, and the cavity in the interior 
is so much smaller that it can scarcely be recognized ; the 
twist of the fibre is also considerably increased. 

By this treatment the fibres become also more solid and 
firmer and in dyeing behave differently from ordinary ma- 
terials. With the use of the same dyeing liquor they ac- 
quire a much fuller tone of color, and the same result is 
obtained with smaller quantities of coloring matter than 
otherwise would be possible. 

This peculiar behavior of the cotton fibre was discovered 
by John Mercer and introduced by him in the practice of 
cotton dyeing. The term mercerization has been applied to 
the process, and it is much used at the present time. 

By treating cellulose with highly-concentrated solution of 
caustic alkalies it is largely converted into oxalic acid. 

By treating cellulose with a suitable quantity of caustic 



CELLULOSE. 15 

soda and then adding to the mass a certain quantity of car- 
bon disulphide, a thickly-fluid solution is obtained which is 
distinguished by an extraordinary adhesive power. By 
heating, the solution is again decomposed, whereby the car- 
bon disulphide is volatilized and the cellulose passes again 
into an insoluble form. 

BEHAVIOR OP CELLULOSE AT AN INCREASED TEMPERATURE. 

Cellulose exposed in a close vessel to a higher tempera- 
ture commences to decompose at about 302° F., and when 
the temperature is constantly increased there remains fin- 
ally a lustrous black coal. By this heating, or destructive 
distillation as it is called, various products, partially gase- 
ous, partially fluid or solid, are formed. The gaseous pro- 
ducts form to upwards of 30 per cent, of the weight of the 
cellulose, and consist chiefly of varying quantities of car- 
bonic acid and carbonic oxide. The fluid products separate 
in two layers, one of them being of an aqueous nature and 
amounting to about 40 per cent, of the weight of the cellu- 
lose, while the other represents a thick, viscous mass — the 
so-called wood tar — of a dark brown, nearly black, color, 
which amounts to from 4 to 6 per cent, of the weight of the 
cellulose. 

The aqueous fluid, the so-called wood vinegar, contains, 
besides water, considerable quantities of acetic acid, acetone, 
methyl alcohol, small quantities of butyric acid and other 
combinations. The wood tar consists of a large series of 
hydrocarbons which are partially fluid or of an oil-like 
nature, while other constituents, to which belongs parafline, 
are at the ordinary temperature solid and crystalline. 

It will be seen from the brief explanations given above 
of the behavior of cellulose towards the action of chemicals 
and of the effect of higher temperatures upon it, that it 
forms the basis-material of a large series of combinations of 
great technical importance. In the forms in which it is 
yielded by the so-called textile plants, it constitutes the 



16 CELLULOSE, AND CELLULOSE PRODUCTS. 

chief material of the textile industry and partially supplies 
the material for the manufacture of paper, though for the 
latter purpose the artificial product furnishes an exceed- 
ingly valuable substitute. Cellulose is further used in the 
manufacture of most of the blasting materials and explosive 
bodies, for the preparation of viscose, celluloid and several 
other substances, and it maj'', therefore, be properly called 
one of the most important raw materials of the textile and 
chemical industries. 

INDUSTRIAL USES OF CELLULOSE. 

Cellulose and its derivatives are used for many purposes, 
and the object of the enumeration here given is simply to 
show in a comprehensive manner the great importance of 
these bodies for the various industries. 

Pure cellulose as at present prepared from wood is most 
extensively employed in the manufacture of paper and con- 
siderable quantities of it are also used for the manufacture 
of fire-proof paste-board for roofing (carton pierre), for the 
preparation of plastic masses, and as an excellent filter 
material. 

The term vegetable parchment has been applied to cellulose 
in the form of paper which has been changed by subjecting 
it for a short time to the action of concentrated sulphuric 
acid. On account of its strength it is used for book bind- 
ings, as well as a dialyzer in various chemical industries, 
for instance, in the manufacture of sugar. 

CeUulose sulphocarbonate or viscose is used as a sizing 
material for dressing tissues, as a thickening substance in 
calico-printing and for the preparation of textile threads. 
In the course of time, it very likely will also be applied to 
other purposes. Solutions of pure cellulose in cuprammon- 
ium are at present used in a similar manner to viscose for 
the production of textile threads. 

To the important derivatives of cellulose belong the com- 
binations to which the general term of nitrocelluloses has 



CELLULOSE. 17 

been applied. Some of these combinations are distin- 
guished by great explosive power and are extensively used 
for the preparation of blasting agents, while others, which 
are soluble in certain fluids, form with them the so-called 
collodion which is used in surgery and photography and, 
in modern times, also for the preparation of textile threads 
to which the term artificial silk has been applied. 

The peculiar substance formed by bringing together 
nitrocellulose wath certain hydrocarbons and known as 
celluloid has found many applications in the industries and 
arts. 

The general suggestions which have here been made as 
to the utilization of cellulose and its derivatives suffice to 
prove that they belong to the most important bodies avail- 
able to the industries. 

The conversion of cellulose into fermentable sugar, and 
of the latter into alcohol, being actually possible, it is not 
unlikely that some time or another in the future a process 
will be perfected by means of which the production of 
alcohol from cellulose, relatively wood, will be more 
profitable than from plants containing starch. Since alco- 
hol itself forms the initial material for the preparation of 
many other chemical products, such as ether, vinegar, etc., 
a new field for the utilization of cellulose would be opened 
and the import of the invention of a suitable process for 
the production of alcohol from wood can scarcely be esti- 
mated. Present experiences in this line, though encour- 
aging, are not sufficiently perfected for their application on 
a large scale. However, it maj^ be fairly asserted that the 
rational preparation of alcohol from wood is only a ques- 
tion of time. 

PRODUCTION OF CELLULOSP:. 

Up to modern times — about the first half of the nine- 
teenth century — no other sources for cellulose than certain 
parts of plants were known, fn warmer countries where 
2 



18 CELLULOSE, AND CELLULOSE PKODUCTS. 

the cotton plant thrives, the hair which grows around the 
seed and which consists almost of pure cellulose, formed the 
material for the preparation of textile threads. In coun- 
tries having a colder climate, flax, as well as hemp, has 
from time immemorial been the principal source of cellu- 
lose fibres. 

In addition to the plants mentioned above, a number of 
others were to a more limited extent utilized in other parts 
of the globe for the production of cellulose. However, the 
use of such plants was merely local, while that of cotton, 
flax and hemp was universal. 

Since communication with cotton-producing countries 
has been greatly facilitated, this material has been gen- 
erally adopted in Europe and has in many cases displaced 
flax for the production of textile fibres. 

Paper consists of cellulose fibres felted together in a 
peculiar manner, and formerly linen rags were exclusively 
used for its manufacture. In consequence of the enormous 
increase in the consumption of paper the price of rags ad- 
vanced constantly, and it became necessary for the paper 
manufacturer to find other sources of cellulose suitable for 
his purposes. 

It had for a long time been known that unlimited 
quantities of cellulose were available in the higher plants, 
the larger part of their tissues consisting of it. However, 
this cellulose occurs in such a form that no means were 
known by which it could be separated in a suitable shape 
for the manufacture of paper. 

The first experiments made in this direction were for the 
purpose of obtaining the cellulose contained in the straw of 
the various kinds of grain. The results of these experi- 
ments were, however, satisfactory only in so far that a 
material was obtained which at the best was only suitable 
as an addition to the cellulose mass prepared from rags. 
When used by itself for the manufacture of paper, the re- 
sulting product was of a very inferior quality as to appear- 



CELLULOSE. 19 

ance and solidity. A substance suitable for the manufacture 
of paper was obtained from maize straw and yielded some- 
what better results, Alois Auer, formerly director of the 
Austrian government printing-office at Vienna, deserving 
special credit for his efforts in this respect. 

As might be expected, many experiments were made for 
the purpose of obtaining the cellulose contained in wood, 
but none of them was successful because no means were 
known to bring into solution the encrusting substance by 
which the individual vascular bundles are cemented 
together. 

However, the production from wood of a material which 
would at least serve as a partial substitute for cellulose, in 
the manufacture of paper was finally successfully accom- 
plished, though the paper made from it was inferior in 
quality to the product from pure cellulose. 

This substitute consisted of wood reduced to a more or 
less fine condition by mechanical means. The reduction 
was effected by means of grindstones, and large works for 
the manufacture of this material w^ere established. How- 
ever, this wood pulp prepared by mechanical processes was 
nothing but wood, and could only be mixed in certain pro- 
portions with the pulp prepared from rags, and the result- 
ing paper was of an inferior quality. It was brittle and its 
color was not pure, and by exposure to light soon turned 
brownish. It constituted, however, a valuable material for 
newspapers and other printed matter intended for tem- 
porary purposes. In the manufacture of paper, wood-pulp 
prepared by mechanical means is at present onlj'^ used for 
very ordinary grades ; it is, however, extensively used in 
the manufacture of paste-board. 

By the efforts of chemists a process was finally found by 
means of which it was rendered possible to prepare from 
wood pute cellulose of such a quality as to be suitable for 
the better grades of paper, and from this period on' dates a 
great revolution ia the manufacture of paper. 



20 CELLULOSE, AND CELLULOSE PRODUCTS. 

A process was discovered by which the complete solution 
and destruction of the lignin or encrusting substance of the 
wood is made possible, so that the individual vascular 
bundles are deprived of their coherence and fall apart, and 
after removing the solvent and bleaching, appear as pure 
cellulose. 

Thus far only two groups of bodies are known which 
may be used for the destruction of the encrusting substance, 
namely, the caustic alkalies, alkaline sulphites, and chlorine, 
and one or the other group of these combinations is em- 
ployed in every process, no matter under what name it 
may be known, for the preparation of cellulose. 

To judge from the present state of the industry, the ques- 
tion as regards the preparation from wood of cellulose suit- 
able for the manufacture of paper would, therefore, appear 
to be solved. However, there remains the solution of a no 
less important problem, namely, the production from wood 
of cellulose of such a quality as to render it suitable for the 
preparation of textile threads. Many experiments have 
been made in this direction, but without entirely satis- 
factory results, it having thus far been only possible to 
make cellulose threads a few millimeters long, while fibres 
of considerably greater length are required for textile 
purposes. 

There can scarcely be any doubt that this question will 
also be solved in the course of time, and we will then have 
in wood-cellulose a material available for the manufacture 
of paper, as well as for weaving tissues, and which will to a 
considerable extent be detrimental to the cultivation ot 
cotton and flax. 

With reference to what has been said above, two phases 
of the historical development of the production of cellulose 
from wood will have to be kept in view, the one in which 
the efforts were directed towards the preparation by 
mechanical processes of a material suitable for the manu- 
facture of paper, and the other, in which the efforts led to 



CELLULOSE. 21 

the production of pure cellulose from wood. According to 
the nature of the chemicals used, the manufacture of cellu- 
lose may be divided into that of soda-cellulose, sulphite- 
cellulose and electro-chemical-cellulose. 

As has been previously mentioned, the problem of pro- 
ducing textile threads from wood has thus far not been 
satisfactorily solved, though such threads are at the present 
time made in a roundabout way from cellulose. As this 
subject will be fully discussed later on, it need here be only 
briefly referred to. From wood, pure cellulose can only be 
obtained in the form of short fibres, but fluids are known 
in which the cellulose dissolves without undergoing a 
change as regards its physical and chemical properties. 
These solutions can be converted into very long and ex- 
tremely thin threads, from which the cellulose can be sep- 
arated so that it retains all its original properties. Threads 
thus produced may be spun into yarn like other textile 
fibres and from such yarn fabrics can be made which do 
not differ from other cellulose tissues, except that they 
present a more beautiful appearance as regards smoothness 
and lustre. It will thus be seen that, even at the present 
time, cellulose from wood may actually be obtained — 
though in an indirect way — in the form of textile fibres. 



II. 

WOOD-STUFF, OR MECHANICAL WOOD-PULP. 

The term wood-stuff or mechanical wood-pulp, is applied 
to wood converted by purely mechanical means into a fine- 
fibred mass, which by itself may serve for the production 
of coarser grades of paste-board, as well as for the manu- 
facture of various articles. Its chief use, however, is as an 
addition to paper stock for the manufacture of inferior 
grades of paper. Although wood-stuff, if properly pre- 
pared, is sufficiently fine-fibred to be made into paper in 
the paper machine, it is not used by itself for this purpose, 
because such paper possesses the disagreeable property of 
becoming darker, and acquiring in a short time a brown 
coloration when stored exposed to the light. The cause of 
this phenomenon is found in the fact that the wood-stuff 
still contains nearly the entire quantity of encrusting sub- 
stance, lignin, etc., originally present in the wood, these 
substances being subject to great changes. Hence, in the 
course of time efforts were made to remove these substances 
from the wood, so that only pure cellulose remains behind, 
which, as it does not show the above-mentioned defects, can 
be used by itself for the manufacture of paper. 

The process of grinding wood has been known for a com- 
paratively long time. The fundamental idea originated 
with F. G. Keller, of Hainichen, Saxony, and was so far 
perfected by him in conjunction with Heinrich Voelter^ of 
Heidenheim, Wurtemberg, that as early as 1846, the first 
patents for wood-grinding processes were granted. In the 
second half of the 19th century, wood-grinding processes 
were introduced in all countries abounding in varieties of 

(22) 



WOOD-STUFF, OR MECHANICAL WOOD-PULP. 23 

wood suitable for the purpose, and the bulk of paste-board, 
as well as that of ordinary newspaper, is made from ground 
wood. 

Voelter's process of wood grinding is executed as follows : 
Suitably prepared blocks of wood are pressed against a 
rapidly revolving grindstone which is kept constantly wet 
by water. By the grindstone the wood is reduced to a 
mixture of fine fibres, larger shreds, quite large shavings, 
and water. This mixture is first caused to press against a 
quite coarse wire screen which retams the coarser shavings 
and splinters. From this screen the mass is led through a 
series of cylindrical screens covered with wire gauze increas- 
ing in fineness, so that from the last screen a thin paste 
consisting of the finest wood fibre and water runs off. The 
separation of the wood fibres from the water is effected in 
various ways, it being frequently accomplished by allowing 
the paste to flow over an endless fine-meshed metallic cloth. 
The water runs off through the meshes while the fibres in 
the form of a delicate pulp remain upon the cloth, and may 
be still further freed from water by rolls. In this case, the 
pulp is very frequently conducted at once to the rolls of the 
paper machine where it is converted into sheets of fixed 
size. According to another method, the pulp is allowed to 
drain off in large boxes and is then freed from water by 
pressing. 

WOOD FOR GRINDING. 

Although every kind of wood may be ground, the differ- 
ent varieties are by no means alike suitable for the pur- 
poses for which the pulp is to be used. Of the European 
varieties of wood, asp, linden, fir, pine and birch are espe- 
cially well adapted for the purpose, while beech is less 
suitable. In America the soft white wood of the tulip tree 
(Liriodendron tulipifera) commonly called poplar, as well as 
the wood of spruce and pine, is used in large quantities for 
mechanical wood-pulp. 



24 



CELLULOSE, AND CELLULOSE PRODUCTS. 



The soft white woods of the asp and linden yield a beauti- 
ful white pulp, which, however, does not act to advantage 
in the paper-stuff, paper prepared with such pulp turning 
out soft and spongy. The pulp from pine or fir, to be sure, 
is not quite so white, but can be worked into firm, smooth 
paper. 

Before being subjected to the grinding process the wood 
must be carefully examined and prepared. Decayed or 
rotten wood should be absolutely rejected since the resulting 
pulp would have a brownish color, and when allowed to lie 
for some time in a moist state would become mouldy 
throughout. Hence only sound, clean wood should be 
worked. 



PREPARATION OF THE WOOD TO BE GROUND. 

The preparation of the wood for the grinding process is 
effected by means of special machinery. The blocks of 



Fig. 4. 




wood are first submitted to a machine, which is a sort of 
revolving plane, and cuts away the bark. Such a machine 



WOOD-STUFF, OR MECHANICAL WOOD-PULP. 



25 



is^shown in front and side views in Figs. 3 and 4. As will 
be seen from Fig. 3, three knives are fixed to the rapidly 
revolving drum. By conducting the blocks of wood against 
these knives, the bark is cut away, care being taken to see 
that it is completely removed, otherwise the pulp will in- 
evitably show dark spots. 

Since knotty wood cannot be properly ground, the knots 



Fig. 5. 




have to be removed, various kinds of machinery being 
used for this purpose. A machine of simple construction 
is shown in Fig. 5, the removal of the knots being effected 
by means of a rapidly revolving auger. Another machine 
for the purpose, Fig. 6, is furnished with a spoon-shaped 



26 



CELLULOSE, AND CELLULOSE PRODUCTS. 



auger, which is set in rapid motion by the bevel gear, Fig. 7. 
The blocks of wood thus prepared are cut by means of a 
circular saw into pieces of such a length that they can be 
laid in the individual pockets of the grinding apparatus. 
Each block is finally split into at least two pieces by means 



Fig. 6. 




Fig. 7. 




of a splitting machine, Fig. 8. The chief object of this 
splitting is not so much to chop up the wood as to give an 
opportunity for examining it inside, since many blocks ap- 
pearing perfectly sound from the outside may be rotten at 
the core, and hence of no use for the preparation of pulp. 

When the wood has been thus freed from bark and knots, 
and on splitting been found to be sound throughout, it is 
ready for the grinding machine. 



WOOD-STUFF, OR MECHANICAL WOOD-PULP. 27 

WOOD-GRINDING MACHINES. 

Every kind of machine for grinding wood consists of a 
grindstone, generally of fine-grained sandstone, which re- 
volves with great velocity around its axis, and against the 
surface of which the wood is pressed, the latter being kept 
constantly wet with water. The wood is placed so that its 
vascular bundles lie parallel to the surface of the grind- 
stone. The latter in revolving tears from the wood indi- 

FiG. 8. 



vidual vascular bundles, as well as entire groups of them, 
and not seldom even larger splinters. The mass torn loose 
is carried by the water into a vat, in which the revolving 
stone is placed, and from there to the sorting contrivances, 
by which the different-sized particles of wood are separated 
one from the other. 



28 CELLULOSE, AND CELLULOSE PRODUCTS. 

The oldest of these machines is that constructed by 
Voelter, and it has proved so satisfactory that up to the 
present time it has undergone but slight modifications, its 
main features remaining the same. 

In Voelter's, as well as in other machines built in imita- 
tion of it, the grindstone is fixed to a horizontal shaft, but 
in some more modern constructions, to a vertical shaft. 
However, a horizontal position of the shaft is considered 
more suitable by all who have had the opportunity to test 
the capacity of the different machines. 

voelter's grinding machine. 

Voelter's grinding machine, Fig. 9, consists of a frame 
having two strong, cast-iron sides firmly bolted together and 
supporting the bearings of the grindstone. One side of the 
frame is so arranged that the sheet-iron jacket can be re- 
moved so as to allow of the grindstone being readily ex- 
changed without the necessity of taking the entire machine 
apart. Between the two sides, fixed to their surfaces, are 
pockets or boxes, in which the wood to be ground is placed. 
The blocks of wood are pressed against the grindstone by a 
spur gearing, uniform pressure being kept up by means 
of a tight endless chain. The arrangement of this mechan- 
ism is such that when one pocket becomes disengaged, the 
others receive a somewhat stronger pressure, the uniform 
running of the machine being thus constantly maintained, 
and one or two pockets may be refilled without stopping 
the machine. 

The grindstone is somewhat wider than the blocks of 
wood to be ground, and is furnished with a mechanical 
contrivance by means of which, while it revolves, it can 
alternately be shifted towards the right and the left. The 
effect of this arrangement is that not only the stone wears 
more uniformly, but its disintegrating action upon the 
wood is also increased. The pockets in which the wood is 
placed have the form of truncated pyramids. Each pocket 



WOOD-STUFF, OR MECHANICAL WOOD-PULP. 



29 



is provided with a strong, cast-iron cover which is pressed 
down by the racks connected with the spur wheels, the 
latter being constantly drawn down by the endless chain. 
When a pocket has been filled with wood, the cover is 
placed in position and, by engaging the spur wheel, is 
firmly pressed upon the wood, and the latter is then sub- 
mitted to the grinding action of the stone. Each pocket is 



Fig. 9. 




furnished with a pipe through which an abundance of 
water is constantly conducted over the wood and the stone. 
The fragments of wood detached by the stone, being imme- 
diately washed away, fall to the bottom of the vat, and are 
carried to the sorting screens. As the water is generally 
introduced in fine jets under high pressure, the detached 
particles of wood are sure to be washed away by the force 



30 



CELLULOSE, AND CELLULOSE PRODUCTS. 



thus brought to bear upon them, and there is no danger of 
the machine becoming clogged by splinters. 

There are numerous constructions of machines in which 
the grindstones are placed vertically, but in principle they 
do not differ from Voelter's machine. Some of them, how- 
ever, show certain improvements as regards the mode of 
pressing the blocks of wood against the grindstone. 

Fig. 10. 




A. Oser's machine, Fig. 10, is so arranged that a constant 
and adjustable pressure upon the blocks of wood by the 
endless chain is produced by means of a movable crank, a, 
which receives its impulse from the shaft of the stone, 
further by the spring-connecting rod, h, the contrivance for 
engaging the binding attachment, c, and the connecting 
gear, which is set in motion by the wheels, d e and / g. 



WOOD-STUFF, OR MECHANICAL WOOD-PULP. 



31 



Fig. 11 shows Voith's wood-grindiner machine, which 
differs but little from the one described above. 

freitag's grinding machine. 
This is an original construction of a grinding machine 
with stones fixed to a perpendicular shaft. Four or five 

Fig. 11. 




grindstones, each having a diameter of only about 20 
inches, are used, and their bearings are so arranged that the 
surfaces of all the stones can be adjusted at exactly the same 
height. The wood to be ground, in the form of a long 
block. Fig. 12, is laid upon the stones, pressed against them 



32 



CELLULOSE, AND CELLULOSE PRODUCTS. 



by means of an iron plate, and, during the process of grind- 
ing, is to a fixed extent moved to and fro. This grinding 



Fig. 12. 




apparatus is said to furnish especially long fibres which is 
certainly of great advantage for the quality of the pulp. 

abadie's grinding machine. 
Of an entirely different construction are the wood-grind- 
ing machines in which one of the circular surfaces of the 

stone is used as the grind- 
^^*^- 1^- ing plane, as is the case in 

the machine constructed 
by August Abadie. This 
machine, Figs. 13 and 14, 
is furnished with four 
press-pockets, h, the pis- 
tons of which are loaded 
with the weights, k. The 
load may be increased by 
tlie use of the connecting 
gears fixed above k, which 
serve also for raising the 
press-pockets when they 
are to be refilled. In the spaces i between the press-pockets, 
weights of iron, stone or wood are to be placed, their object 
being immediately to grind up the wood-stuff detached by 
the grindstone. This specification, however, has yet to be 
proved by direct experiments. 

It is a matter of experience that the wood-stuff detached 




WOOD-STUFF, OR MECHANICAL WOOD-PULP. 



33 



Fro. 14. 



from the blocks of wood in one press-pocket, should as 
rapidly as possible be withdrawn from the further action of 
the machine, since the fibres, when dragged again into 
another pocket and there again exposed to the action of the 
grindstone, are too much reduced or what is technically 
called dead-ground. This contingency need not be feared in 
Abadie's machine, since the water is supplied from the 
centre of the machine so that it 
is forced outward by centrifugal 
force and immediately carries 
away all the particles of wood 
lying in its course. The indi- 
vidual pockets or presses are 
fixed in a frame g, and the 
latter is pressed firmly against 
the grindstone by three per- 
pendicular screws /, and ac- 
curately centered by three 
horizontal screws. 

In addition to the construc- 
tions above described, there are 
a few other wood -grinding 
machines in which the stone is 
fixed to a vertical shaft, so that 
its entire surface may be set 
with press-pockets. In an ap- 
paratus of this kind, con- 
structed by Liebrecht, eight 
grinding pockets in all are 
used, and the wood is pressed 
against the grindstone by hydraulic pressure. Such a 
machine, of course, can in the same time work up a larger 
quantity of wood than one with only four or five grinding 
pockets, but it must also be borne in mind that the con- 
sumption of power is correspondingly greater and that the 
grindstone is subject to much greater wear. 
3 




34 CELLULOSE, AND CELLULOSE PRODUCTS. 

Regarding the use of hydraulic pressure for pressing the 
wood against the grindstone, Liebrecht's construction in 
this respect must be acknowledged as a very ingenious one. 
However, the apparatus becomes, thereby, more expensive 
and more complicated, two factors which are not in favor 
of a machine on which heavy demands are made. 

In construction, Voelter's wood-grinding machine is 
more simple than any other apparatus for the same pur- 
pose, and the unexpected giving-away of any important 
part can scarcely happen ; furthermore, the grindstone can 
be readily removed and in a short time replaced by another 
one. With this machine, as shown by practical experience, 
operations can be carried on for a long time without having 
to stop work for more extensive repairs. 

WATER USED FOR GRINDING. 

Regarding the water which during the grinding opera- 
tion has to be constantl}'' conducted upon the grinding sur- 
face, it may be mentioned that it should be perfectly clear 
and free from suspended solid bodies — especially sand or 
clay. Such bodies would, of course, adhere to the pulp 
and affect its purity, this being especially the case with par- 
ticles of clay contained in the water used. Pulp from a 
variety of wood which otherwise would yield a nearly white 
product, acquires by a content of clay — according to the 
color of the latter — a yellow or gray appearance. 

Hence, when in the locality where a grinding plant is to 
be established, perfectly clear water, free from sand or clay, 
is not available, it would seem advisable to pass the water 
required for grinding through a filter which retains the 
suspended solid bodies. In order to economize, in this case, 
with filtered water, the water running off" from the sorting 
screens is not allowed to flow away, but is collected in a 
basin and pumped into a reservoir placed at a higher level, 
from which it is reconducted to the grinding apparatus. 



WOOD-STUFF, OR MECHANICAL WOOD-PULP. 35 

SORTING THE GROUND MASS. 

The operation subsequent to the grinding process consists 
in separathig the different-sized particles detached by the 
grindstone from the blocks of wood. The general term 
sorters is applied to the various contrivances used for the 
purpose. 

Before commencing the actual sorting operation, the fluid 
coming from the grinding apparatus is passed through the 
so-called splinter-catcher. The latter consists of a larger 
vessel in which sits a cylinder with slit sides, or covered 
with a wire screen. The cylinder revolves slowly around 
its axis and frequently is also kept in an oscillating motion. 
The particles of wood, which are small enough to pass 
through the slits or meshes of the cylinder, are carried, 
together with the water, to the sorters, whilst the coarser 
splinters collect in the box of the splinter-catcher, to be 
further reduced in special mills. 

The sorters, which serve for sorting the wood-stuff, re- 
semble in the main other appliances used for similar pur- 
poses. They consist either of a series of sieves of gradually 
increasing fineness which are kept in a shaking motion, or 
of revolving cylinders covered with wire sieves. In place 
of revolving cylinders, hexagonal prisms covered with wire 
sieves are also used. 

Voith's shaking sieves are shown in Figs. 15 and 16. 
The sifting frames consist of sheet iron, the ends being 
turned up. Each frame rests upon four steel springs, d — d, 
e — e and / — -/, and is connected with a spring-connecting 
rod, g h i. The cranked axle lies in k I, its crank-pins being 
placed one against the other at an angle of 120°, whereby, 
in connection with the fly-wheel, a quite uniform running 
of the machine is attained. 

The sieves are kept in a very rapid jerking or shaking 
motion — 400 to 500 motions per minute. By the use of 
springs, as applied in the above-described machine, the 
otherwise great wear and tear of the machine is reduced 



36 



CELLULOSE, AND CELLULOSE PRODUCTS. 



and the very loud noise made by the shaking sieves is con- 
siderably modified. 

The mode of operation of the shaking sieve is a very 
simple one : The mass, consisting of particles of wood and 
water which comes from the splinter-catcher, falls upon the 

Fig. 15. 




uppermost sieve. Water and all particles of wood smaller 
than the meshes fall through the sieve, whilst the coarser 
particles slide down over it and collect in a receptacle. 
The same process is repeated in the succeeding sieves, and a 
pulp of delicate particles of wood and water runs finally 
from the lowest and finest-meshed sieve into the settling vat. 



Fig. 16. 



;^gjA 




With the use of cylinder-sieves the same process takes 
place in a revolving cylinder, in which the mass coming 
from the splinter-catcher is freed from the coarser particles, 
then passes to the succeeding narrower-meshed cylinder- 
sieve, and so on. Instead of arranging three or more 



WOOD-STUFF, OR MECHANICAL WOOD-PULP. 37 

cylinder-sieves one after the other the sieves may also be 
fixed one inside the other so that they revolve towards each 
other in opposite directions, the second revolving in an 
opposite direction to the first outermost, and the third again 
in the same direction as the outermost. 

The mass coming from the splinter- catcher passes into 
a trough into which the outermost sieve dips, and being 
carried along by it, reaches the second sieve, and from this 
finally the innermost one. 

The particles of the ground wood which have passed 
through the sieve with the narrowest meshes are considered 
of sufficient fineness not to require further manipulation. 
Hence this pulp is directly conducted to the settling vats, 
the dehydrating apparatus or the board machines. 

The particles of wood which are not sufficiently ground 
have to be further reduced, the simplest manner of accom- 
plishing this being by means of mill-stones of ordinary con- 
struction. However, special mills which are better adapted 
for this purpose have also been constructed. Such a mill, 
known as a refiner, is shown in Figs. 17 and 18. 

This mill differs from the ordinary constructions in being 
furnished with two stationary millstones placed in a verti- 
cal position, between which revolves a runner dressed on 
both sides. Since this stone possesses two grinding planes, 
the same performance can be attained with one stone of 
small diameter as with much larger stones in an ordinary 
mill. In the illustrations, A, B, represent the three stones, 
the middle stone B being fixed by means of a box-screw to 
the shaft D. The stones A and C sit upon the carriage 
F F, and are firmly fixed to it by the screws u and u. Z is 
a jacket enclosing the stones, and the carriage F F, together 
with the stones, can be shifted in it. The shifting of the 
stones for the purpose of regulating the distance between 
them is effected by means of the wheel J. Both stones are 
simultaneously shifted upon the support Z, the shaft H 
being furnished with a left and right thread. S represents 



38 



CELLULOSE, AND CELLULOSE PRODUCTS. 



the contrivance for the introduction of the wood. It is 
fixed to the jacket Z by means of the iron supports r r, and 
terminates in two outlets t t. /S* is a gutter also furnished 
with two outlets, so that the wood to be ground reaches the 
grinding surface by means of t i, the channels W W, and 
the two exterior sides of the stones, the latter receiving it 
only upon the lower halves of their circumferences. The 
wood remains between the stones only long enough to be 

Fig. 17. 




reduced to a degree of fineness corresponding to the distance 
between the stones, when it falls down on its own account. 
In place of the refiner, finely corrugated rolls may be 
used for the reduction of the particles of wood. They re- 
volve with difierent velocities whereby the wood is at the 
same time torn and crushed. The wood thus reduced is, 
for the sake of precaution, passed through a fine-meshed 
sieve in order to retain coarser particles which may have 
escaped the action of the mill, and finally reaches the con- 



WOOD-STUFF, OR MECHANICAL WOOD-PULP. 



39 



trivances for the separation of the pulp from the water. 
These contrivances consist of revolving cylinders covered 
with fine gauze-wire sieves so that the water, but not the 
pulp, can pass through. By this means, the pulp, to be 
sure, loses considerable water, but is not sufficiently freed 
from it, the use of special apparatuses being required for 

Fig. 18. 




the complete removal of the water as far as it is at all pos- 
sible. 

The water running off from the dehydrating cylinders 
always carries with it a certain quantity of the finest par- 
ticles of the pulp which is sought to be recovered in various 
ways, sieves of the finest gauze wire being most frequently 



40 CELLULOSE, AND CELLULOSE PRODUCTS. 

used for the purpose. The water flows over the sieve while 
the air is exhausted underneath it. The water penetrates 
through the meshes while the pulp remains upon the sieve, 
and is removed from it by a scraper. 

DEHYDRATION OF THE PULP. 

The removal of water, as far as possible, from the pulp is 
an important operation, especially if the pulp is to be 
shipped, because the smaller the content of water the less 
the expense for freight will be. If the pulp is to be used 
in the establishment itself in which it is prepared, thorough 
dehydration is of course not required, it being only necessary 
to free it from water sufficiently to allow of the preparation 
of boards, in which state it is further worked, the finished 
boards being finally completely dried. 

The board machine consists in the main of an endless 
cloth 10 to 13 feet long which is stretched tight over rolls 
so as to present a perfectly level surface. Over this cloth, 
several wooden rolls lie loose in crotches, their object 
being to distribute uniformly the quite thinly-fluid pulp 
taken up by the endless cloth and, at the same time, to 
somewhat squeeze it out by their weight. By this means 
quite a tenacious paste is obtained on the portion of the 
endless cloth opposite to where the pulp enters. This paste 
is then pressed more vigorously between two iron rolls so 
that it forms a quite firm, coherent mass. This is allowed 
to wind several times round a roll and the hollow cylinder 
thus formed is cut through, all the sheets thus produced 
being of the same size. Sheets of any desired length may 
also be formed upon an endless cloth which takes up the 
pulp. If, however, in place of sheets thoroughly dried, or 
more correctly, thoroughly dehydrated, pulp is to be pro- 
duced, the pulp is allowed to flow over a cylinder covered 
with wire cloth, both ends of which are rendered as tight as 
possible by rubber, and under which vigorous rarefaction 
of air is maintained. The pulp flowing upon the slowly 



WOOD-STUFF, OR MECHANICAL WOOD-PULP. 41 

revolving sieve is much dehydrated by the air-pressure and 
is removed in the form of a coherent mass. It is then 
again vigorously pressed between rolls and finally divided 
by smooth rolls into small pieces which are immediately 
packed. 

If, however, the pulp is to be freed as much as possible 
from water as would seem necessary for transporting it long 
distances, filter-presses are used, a quite powerful hydro- 
static pressure being produced by means of an accumulator. 
In the chambers of the press, sheets quite dry to the touch 
are thus obtained, which can be readily packed and trans- 
ported long distances. The only drawback as regards the 
use of filtering-presses is that a plant working on a larger 
scale would require a number of them to work up rapidly 
all the raw material furnished by the grinding machine. 

DRYING APPARATUS. 

The preparation of perfectly dry pulp has recently been 
successfully accomplished without too large an expenditure^ 
by the use of apparatus which in its construction closely 
resembles the contrivances employed in sugar houses and 
breweries for drying beet slices and grains. They are so 
arranged that the substance to be dried moves in a direc- 
tion opposite to that of a hot air current, so that drying is 
effected by a counter-current. The substance to be dried 
is first met by the hot air-current while it still contains all 
the water, and though it becomes highly heated, it loses 
but little water by evaporation, the latter process, however, 
proceeding very rapidly as the heated mass advances. 

The apparatuses used for drying pulp are generally so 
arranged that the crumbled pulp previously freed as much 
as possible from water by mechanical means, is carried 
a,long with a certain velocity upon endless wire cloth, while 
underneath the latter a hot air-current passes in an opposite 
direction. The velocity of the movement of the pulp upon 
the cloth is fixed by the temperature, and the latter has to 



42 



CELLULOSE, AND CELLULOSE PRODUCTS. 



be carefully regulated. By the use of such an apparatus 
the pulp may be only partially or completely dried, as may 
be desired. The apparatus is furnished with automatic 
charging and discharging contrivances. 

PROPERTIES OF WOOD-PULP. 

With the exception of pulp completely freed from water 
by artificial drying — and this exception applies only to 
material dried shortly after its preparation — its color under- 
goes a considerable change, which, of course, is also trans- 
mitted to the paper prepared from it. Experiments made 
by CI. Winkler with pulp from different varieties of wood 
which was exposed to the action of the air at a temperature 
of between 30° and 50° F., gave the following results : 





COLOR OF PUXP. 




From 


When freshly prepared 


After several weeks. 


Pine 


pale yellow 


pale yellow 


Fir 


yellow 


yellow 


Scotch fir 


greenish-white 


dirty reddish 


Larch 


pale yellow 


pale yellow 


Aspen 


yellowish-white 


yellowish-white 


Linden 


gray-white 


gray-white 


Maple 


yellowish-white 


yellowish-white 


Beech 


pea yellow 


superficially reddish 


Birch 


yellowish-white 


flesh color 


Alder 


deep yellow 


brick-red 



The change of color appears first upon the surface of the 
moist pulp, spreading from there to the interior, and is, 
without doubt, a process of oxidation. Since pure cellulose 
does not exhibit this change of color, it can only be caused 
by a chemical change of the lignin and eventually of the 
very small quantity of protein substances. The content of 
rosin in the conifers appears to exert but little influence as 
regards the change of color, as will he seen from the be- 
havior of the pulp prepared from them. 

The change in color of the pulp being very annoying as 
regards the paper made from the material, experiments 



WOOD-STUFF, OR MECHANICAL WOOD-PULP. 43 

have been made to overcome this defect by bleaching. Of 
all the bleaching agents experimented with, sulphurous 
acid, produced by burning sulphur, is the only one which 
has proved of value in practice. The simplest mode of 
application is to conduct sulphurous acid into an air-tight 
box which is filled with broken pulp containing 60 per 
cent, of water. The gas is absorbed with avidity by the 
water, and the entire mass is in a short time saturated with 
it. Pulp thus bleached should not be allowed to lie too 
long, since it has been shown that after some time it con- 
tains sulphuric, in place of sulphurous, acid. When the 
pulp is dried in the air, the sulphuric acid acquires a cer- 
tain concentration and has a browning effect upon the pulp. 
Hence the bleached mass should immediately be worked 
further. 

The effect of the sulphurous acid appears to be that, on 
the one hand, it arrests the oxidizing action of the air, and, 
on the other, that it enters with the coloring matter con- 
tained in the pulp into a colorless combination, which, 
however, is in the course of time again decomposed, the 
sulphurous acid being again liberated and slowly oxidized 
to sulphuric acid. 

PULP FROM STEAMED WOOD. 

When treated with water under high pressure and at a 
high temperature even pure cellulose is chemically changed 
and converted into hydrocellulose. Wood, when treated in 
a similar manner, undergoes, however, more far-reaching 
changes, the lignin contained in it being very likely most 
eflPected, because by the treatment with high-pressure steam 
the fibres are considerably loosened, and there is no diffi- 
culty whatever in preparing from such wood a pulp which 
is distinguished by particularly long fibres. 

The quantities of substances which pass into solution by 
steaming vary according to the variety of wood. In steam- 
ing beech 26.75 per cent, passes into solution, 11.19 per 



44 CELLULOSE, AND CELLULOSE PRODUCTS. 

cent, of this being sugar and substances resembling sugar. 
Steamed pine showed a loss in weignt of 19.17 per cent., 
9.07 per cent, of this being sugar and substances alhed to 
it. The latter probably consist chiefly of dextrin-like 
bodies, since the wood extract yields with alcohol very 
heavy precipitates. 

However, in addition to the bodies mentioned above, 
there are formed in steaming wood, combinations like those 
appearing in abundance at the commencement of the de- 
structive distillation of wood. In w^ater in which wood has 
been steamed are found considerable quantities of acetic 
and formic acids. When resinous woods are subjected to 
steaming, considerable quantities of volatile oil escape with 
the aqueous vapor when the pressure in the vessel used for 
steaming is interrupted. 

By steaming the wood acquires a more or less dark 
leather to liver-brown color, and the fibres are very much 
loosened. By reason of this brown coloration of the wood, 
the pulp prepared from it cannot be used as an addition in 
the manufacture of white paper. It is, how^ever, very suit- 
able for the production of stout wrapping paper, because it 
has very long fibres, which, in making it into paper, felt 
together, the resulting product being very durable and 
flexible. 

In its construction the apparatus used for steaming wood 
resembles a cylindrical steam boiler, both upright and hori- 
zontal types being used. It is advisable to line the walls 
of iron boilers with copper, they being in the course of 
time strongly attacked b}'^ the organic acids formed from 
the wood. 

The production of pulp from steamed wood may be 
efi"ected in various ways. When working with the ordi- 
nary grinding apparatus, the wood is prepared in exactly 
the same manner as the ordinary material, i. e., it is freed 
from bark, the knots are cut out, and the blocks are 
finally cut into lengths to fit the pockets of the machine. 



WOOD-STUFF, OR MECHANICAL WOOD-PULP.' 45 

and split. The blocks are then brought into the boiler and 
for 8 to 12 hours treated with steam of 4 to 6 atmospheres. 
The higher the tension of the steam and the longer the 
wood is exposed to it, the more energetic its action upon 
the encrusting substance and the darker the color of the 
wood will be. 

On subjecting steamed wood to a microscopical examina- 
tion, it will be found that the greater portion of the en- 
crusting substance has disappeared and that the vascular 
bundles consisting of cellulose are quite uncovered. By 
long-continued steaming under high pressure, it might be 
possible to bring all the encrusting substance into solution, 
and thus obtain a product which does not essentially differ 
from pure cellulose. However, in practice, this process 
cannot be profitably applied because, on the one hand, by 
long-continued steaming under high pressure, a portion of 
the cellulose itself is hydrolized, causing a considerable re- 
duction in the yield, and on the other, the cost of produc- 
tion is much increased. Hence steaming is continued only 
long enough for the wood to acquire a sufficient degree of 
softness, when it is submitted to the grinding machine. 
In grinding steamed wood much less power is required 
than in working the raw material, which is readily ex- 
plained by the breaking-up of the coherence of the vascular 
bundles by steaming. 

PREPARATION OF MECHANICAL WOOD-PULP BY THE 
CRUSHING PROCESS. 

A process — called by the inventor the crushing process — 
for the preparation of pulp from steamed wood without the 
necessity of grinding, has been invented by Rasch-Kirchner 
of Frankfort-on-the-Main. 

The steamed wood to be worked is first converted into 
small pieces by means of a chopping machine of original 
construction, the arrangement of which is shown in Figs. 
19, 20, and 21. In a strong iron frame, K, rests in the 



46 



CELLULOSE, AND CELLULOSE PRODUCTS. 



bearing, L, the shaft, A, which carries a heavy disk-knife, 
M. The latter in revolving passes the box, D, and by- 
means of the knife, p, cuts the wood only lengthways into 
shavings of fixed size, or lengthways as well as crossways, 
if the cross-slitters, o, are at the same time applied. The 
construction of the machine is such as to allow of its being 
set so that the wood can be cut up in different ways. The 
wood may be placed in an oblique position and the cross- 

FiG. 19. 




sections thus obtained can readily be reduced to pieces. 
By placing the wood so that it is worked perpendicularly 
to its length and bringing the knives which serve for the 
production of cross-slits into activity, shavings If inches 
wide and long and from 0.11 to 0.19 inch thick may be 
obtained. 

The small pieces of wood coming from the machine are 
then still further reduced by mechanical means, they being 



WOOD-STUFF, OR MECHANICAL WOOD-PULP. 



47 



first subjected to the action of a stamping mill in which 
they are reduced to such a degree that they can be trans- 
ferred to the hollander, a machine used in paper mills for 
the disintegration of paper-stuff. In this apparatus the 
mass may be worked till it has become sufficiently uniform 
for the direct preparation of boards in the board machine. 
If, however, loose pulp is to be.pioduced, the sorters em- 



FiG. 20. 




vvAiJ5,^i,i^ii.\-J^\^s\^-^^-vciiii£s\bv^S>x.^\v\-a 



ployed for ground wood have to be used in order to sepa- 
rate the coarser particles from the finer fibres. 

However, the course most generally pursued in working 
the mass obtained from steamed wood, is to manufacture 
from it at once brown boards or stout wrapping paper. A 
pulp with longer fibres being more readily obtained from 
steamed wood than from wood not steamed, boards and 
paper made from it possess greater strength, the boards 
being especially suitable for roofing purposes. Roofs cov- 



48 



CELLULOSE, AND CELLULOSE PRODUCTS. 



ered with such boards properly impregnated with coal-tar 
possess great capability of resisting the action of the 
weather, being perfectly indifferent to water as well as to 
changes in temperature. 

Numerous attempts have been made to bleach the pulp 
from steamed wood, but thus far without satisfactory re- 
sults, no effect worth speaking of being produced on it even 
by the most powerful bleaching agents. It is very likely 



Fig. 21. 




that the coloring bodies formed in steaming wood belong to 
the group of combinations to which the term humus bodies 
has been applied. They are distinguished by a very dark 
brown to black color which it is impossible to lighten up 
by any bleaching agent. 

Physically, ground wood actually differs from, the orig- 
inal material only in that the individual vascular bundles 
-appear to be quite completely separated one from the other. 



WOOD-STUFF, OR MECHANICAL WOOD-PULP. 49 

However, the individual vessels adhering together are still 
firmly connected by the encrusting substance — the lignin — 
this fact being shown by storing the pulp for some time 
exposed to the light, it acquiring in a short time a quite 
strong brownish coloration. This coloration also appears 
in the paper-mass to which the pulp has been added. 
Paper thus prepared turns perceptibly brown when for a 
few weeks exposed to the light, and at the same time be- 
comes brittle. The manufacture of paper which could lay 
claim to durability for a longer time would therefore ap- 
pear impossible with the use of larger quantities of mechan- 
ical wood-pulp, it being possible only when pure cellulose, 
the great stability of which has previously been referred to, 
is employed. 
4 



III. 

PREPARATION OF CELLULOSE FROM WOOD. 

(WOOD-CELLULOSE, CELLULOSE IN THE 

TECHNICAL SENSE 0^ THE WORD, 

CHEMICAL WOOD-PULP.) 

Paper consists of cellulose fibres felted together in a pe- 
culiar manner so that the individual fibres can no longer 
be distinguished. The cellulose which was formerly ex- 
clusively used for the manufacture of paper consisted of 
waste of linen and cotton fabrics, and other vegetable 
fibrous substances. By reason of the constant increase in 
the consumption of paper, the price of this waste, technically 
called rags, rose steadil}^ so that the efforts of chemists 
were for a long time directed towards finding a substitute 
for rags in another vegetable substance. After many ex- 
periments, the results of which, however, were not veiy 
satisfactory, a process was finally discovered which allowed 
of the separation of cellulose from certain varieties of wood 
in such a form as to render it suitable for use in the manu- 
factur^e of paper. The production of cellulose from wood 
has now become a highly developed industry, and every 
3'ear the quantity of raw material worked up becomes larger. 

In the preparation of cellulose from wood, the principal 
point is the removal of the substances which incrust the 
cellulose, and to convert tlie latter into actual wood sub- 
stance, as well as to obtain it in a pure form. It is, how- 
ever, also of importance that the individual fibres should 
be of a certain length to allow of them being properly 
felted together into paper, and the solution of this demand 

(50) 



CELLULOSE FROM WOOD, OK CHEMICAL WOOD-PULP. 51 

presented for a long time many difficulties which, however, 
finally were successfully overcome. 

There are quite a number of methods by which wood 
cellulose may be prepared, but only three of them — namely, 
the soda process, the sulphite process and the electric pro- 
cess — have at present been firmly established in practice. 
The sulphite process, while it yields the same favorable re- 
sults, is far more simple in execution than the soda process, 
and is more and more replacing the latter, many wood- 
cellulose plants at present working exclusively with it. 

Since the encrusting substance of the wood may also be 
destroyed by acids, a series of processes have from time to 
time been introduced, the object of which is to eff'ect the 
disintegration of the wood-fibre by their use, concentrated 
nitric acid, as well as aqua regia — a mixture of nitric and 
hydrochloric acids — having been employed for the purpose. 
However, independent of the great expense connected with 
them, these processes have the further disadvantage that 
it seems next to impossible to keep the operating vessels 
tight, in consequence of which products of decomposition 
of nitric acid escape into the work-room, rendering the air 
of the latter very injurious to the health of the workmen. 
For these reasons, this method of preparing cellulose has 
been entirel}'^ abandoned. It may, however, be mentioned 
that one acid process by which the disintegration of the 
wood is effected with hydrochloric acid, would seem to be 
available, since it yields a very valuable by-product. 

BACHET AND MACHARD's METHOD. 

According to this method thin slices of fir are subjected 
to hot treatment with hydrochloric acid. Four thousand 
eight hundred pounds of fir in thin slices are brought into 
a wooden vessel and after pouring over them 2000 gallons 
of water and 1760 lbs. of hydrochloric acid, the fluid is 
brought to boiling by the introduction of steam, boiling 
being continued for 12 hours. The fluid is then drawn off 



52 CELLULOSE, AND CELLULOSE PRODUCTS. 

and neutralized with calcium carbonate. It now represents 
a dilute solution of grape sugar which can be brought by 
yeast into vinous fermentation, and by distillation yields a 
considerable quantity of alcohol. The residue consisting 
of cellulose is washed with water . until all the acid is re- 
moved, crushed under millstones and disintegrated in the 
hollander. Since by this process a considerable portion of 
the cost of manufacture is covered by the alcohol gained 
as a by-product, it would appear to be of importance for the 
practice. To judge, however, from its present state, this 
method has many inherent defects which prevent its gen- 
eral introduction. If, however, these defects can be over- 
come, it might prove of importance for the manufacture of 
cellulose. Later on more modern processes for obtaining 
alcohol from wood will be referred to. 

PREPARATION OF CELLULOSE BY MEANS OF SODA. 

This method of preparing cellulose is an American in- 
vention — poplar, pine, spruce, and occasionally birch, being 
used for the purpose. Poplar is especially distinguished 
from other woods in yielding very long-fibered cellulose. 
This process which may be called the American wood-pulp 
system can also be profitably applied to the conifers indig- 
enous to Europe. 

The first step in the manufacture is, in all cases, the 
mechanical preparation of the wood to be worked. This 
consists in carefully freeing the wood, cut up into short 
blocks from the bark, cutting out the knots by special 
machinery and reducing the blocks to chips about | inch 
long, ^ inch wide, and 0.19 to 0.31 inch thick. All the 
mechanical operations : Freeing from bark, cutting out 
knots, etc., are carried out by special machines. 

The disintegration of the encrusting substance of the 
wood is effected by means of caustic soda lye. The state- 
ments regarding the quantities of soda lye — relatively of 
caustic soda — required for working 220 lbs. of wood vary 



CELLULOSE FROM WOOD, OR CHEMICAL WOOD-PULP. 58 

very much, but the quantity of caustic soda obtained from 
48.4 lbs. of carbonate of soda is said to be sufficient in all 
cases. By the action of the caustic soda, the encrusting 
substance of the wood is destroyed and the resins are 
saponified. When the process of disintegration is finished, 
the fluid is discharged and evaporated in iron pans to dry- 
ness. The residue is heated in a reverberatory furnace 
whereby the acids fixed to the soda are destroyed, carbonate 
of soda remaining finally behind. This carbonate of soda 
is again converted into caustic soda, so that for the next 
operation only a sufficient quantity of fresh caustic soda to 
replace that unavoidably lost in the wash waters is required. 

Sodium sulphite having the same destructive effect upon 
the encrusting substance as caustic soda, it is frequently 
substituted for a portion of the latter. This is effected by 
evaporating the lye which has once been used for boiling 
the wood, together with sodium sulphate, which is quite 
cheap, and heating the residue. By the carbonization of 
the organic combinations contained in the salt-mass, the 
sodium sulphate is reduced to sodium sulphite and a fluid 
is obtained which, when again made caustic, contains, in 
addition to caustic soda, a certain quantity of sodium 
sulphite. 

To free the chips of wood from the encrusting substance 
by boiling them with soda lye in open vessels, would re- 
quire so much time as to make the process scarcely avail- 
able for practical purposes. If, however, the lye is allowed 
to act under increased pressure upon the wood, disintegra- 
tion will be accomplished in a comparatively shorter time 
and with greater rapidity, the greater the pressure is and 
the higher the temperature prevailing in the apparatus. 
In practice a pressure from 6 to 14 atmospheres is used, 
though one from 10 to 11 atmospheres is most frequently 
employed. 



54 



CELLULOSE, AND CELLULOSE PRODUCTS. 



Fig. 22. 



SINCLAIR S BOILER. 

From what has been said above, the construction of the 
boiling apparatus must be such as to be capable of resisting 
the high pressure prevailing in its interior, as its explosion 
might cause terrible accidents. Since, considering the size 
of the boilers, even if constructed of the best quality of 
steel, it is difficult to keep them tight under the high pres- 
sure, of, say 14 atmospheres, prevailing in them, an ingen- 
ious contrivance to de- 
crease the pressure is made 
use of in Sinclair's boiler, 
the actual boiler being- 
enclosed by another boiler 
also made of steel. In 
the inner boiler in which 
the soda lye acts upon the 
wood, prevails a pressure 
of 14 atmospheres, while 
in the space between the' 
inner and outer boilers 
circulates steam of 6 at- 
mospheres, and hence the 
pressure upon the wall of 
the inner boiler is reduced 
to 8 atmospheres. The 
arrangement of Sinclair's 
boiler is shown in Fig. 22. 
The vertical boiler con- 
sists of a cylindrical vessel 
A tapering above and be- 
low. In this vessel stands a second one B, of the same 
form, which, however, is constructed of thin sheet iron, and 
its surface is perforated with holes. Its diameter is such 
that the walls of B are at a distance of 1.18 to 1.57 inch 
from A. B is the portion of the apparatus which serves for 
the reception of the wood. The boiler is charged through 




CELLULOSE PROM WOOD, OR CHEMICAL WOOD-PULP. 55 

the aperture C, and after the operation is finished, the fluid 
is discharged through the pipe Oi. The vessel G serves as 
a storage reservoir for soda lye and is so arranged as to 
allow of the introduction of lye into the boiler during the 
operation without a decrease in the pressure taking place. 
When lye is to be introduced, the lower cock h is first 
opened, and then the upper one h^. The same pressure 
then prevails in the vessel G as in the boiler and lye may 
run into the latter. The entire apparatus is heated by an 
open fire from the fire-place F. The lower portion of the 
boiler is protected by brickwork to prevent its coming in 
direct contact with the flame. The flames pass upwards 
through special flues which are so arranged that the flames 
come on every side in contact with the boiler. 

UNGERER's boiling PROCESS. 

In some systems of boiling wood an entire battery of 
boiling vessels, one connected with the other, is used in- 
stead of a single boiler. When the boilers have been filled 
with wood, soda lye is introduced into the first one, and 
allowed to act upon the wood for some time, for instance, 
one hour. Fresh lye is then introduced into the first boiler 
in such a way that the fluid contained in it is forced into 
the second boiler. In about one hour fresh lye is again 
brought into the first boiler, the lye contained in the second 
boiler being forced into the third one, and so on. Hence 
the wood is constantly treated with fresh lye, and disinte- 
gration is effected more completely and in a shorter time 
than when the wood is always boiled with the same quan- 
tity of lye. The system sketched above has been intro- 
duced by lingerer. In its arrangement the apparatus 
closely resembles the difl"usion apparatuses used in sugar 
houses and in factories for the preparation of dye extracts. 
It seems probable that by this method the object of the dis- 
integration of the wood might be accomplished with cer- 
tainty and in the shortest time. 



5q cellulose, and cellulose products. 

keegan's process. 

This process for the disintegration of the wood b}^ means 
of caustic soda, differs essentially from the methods in 
which the wood is heated under high pressure with soda 
lye. The process in its distinctive features consists in that 
the wood is brought into a vessel from which the air is ex- 
hausted. The cold soda lye is then introduced and the 
pressure upon the fluid raised to 3| atmospheres. When 
it is supposed that the wood is completely saturated with 
soda lye, the lye not absorbed is allowed to run off and the 
vessel is heated to 302° F. The quantity of soda lye 
absorbed by the vessels of the wood suffices to bring into 
solution all the encrusting substances, and one great ad- 
vantage of this process is that the wood treated with lye 
need only be washed with a small quantity of water in 
order to regain from it the greater portion of the soda. 
Hence only a comparatively small quantity of fluid has to 
be evaporated, thus saving considerable in operating ex- 
penses, since the great consumption of fuel conditional to 
the evaporation of a large quantity of lye is one of the 
drawbacks of the process of producing cellulose by means 
of caustic soda. 

The mass of wood boiled according to one of the methods 
above described, consists of cellulose, the interspaces of 
which are filled with the fluid which has been formed from 
the soda lye and the substances absorbed by it. The next 
problem is to obtain this fluid as completely as possible, so 
that the soda contained in it may again be brought into 
use. However, so as not to use too much fuel for evaporat- 
ing the lye, the recovery of the soda should at the same 
time be effected in such a manner that as little fluid as 
possible is obtained. In order to attain this object as com- 
pletely as possible, the system of gradual lixiviation em- 
ployed everywhere in chemical establishments when a solid 
body has to be entirely freed from adhering fluid, is made 
use of in cellulose plants. 



CELLULOSE PROM WOOD, OR CHEMICAL WOOD-PULP. Oi 

In working according to this method a battery has to be 
used in which lixiviation is effected by means of a current. 
The distinctive features of such an apparatus are as follows : 
A number of vessels — ten to twelve — are connected one 
with the other in such a way that when the level of the 
fluid in the first vessel reaches a certain height, the fluid 
running off rises from the bottom through a pipe and can 
flow into the next vessel. When these vessels are filled 
with the mass coming from the boiler and water is poured 
into the first vessel, it will in a short time become mixed 
with the fluid contained in the mass of wood. By now 
allowing more water to run into the vessel, the fluid con- 
tained in it is forced into the next vessel where it becomes 
more enriched with soda. Now, with the use of twelve 
lixiviating vessels, the mass in the first vessel will have 
been twelve times in contact with water at the time when 
the last vessel has just been filled. When water is then 
again poured into the first vessel, a corresponding quantity 
of fluid will run off from the twelfth vessel. This fluid is 
a very saturated soda solution, and the quantity of soda 
contained in it corresponds with that present in the fluid 
discharged from the boiler. The mass of cellulose in the 
first vessel is now completely washed and can be immedi- 
ately bubjected to further working by mechanical means. 

While the first vessel is being emptied, the course of the 
supply ot water is so changed that the second vessel of the 
battery becomes the first and in this manner lixiviation is 
systematically continued. 

A number of contrivances, such as counter-current wash- 
ing machines, wash-drums, etc., have been introduced for 
washing cellulose, which do good service provided they 
fulfill the object of lixiviating the cellulose mass in the 
most complete manner, and with the smallest possible con- 
sumption of water. 



58 CELLULOSE, AND CELLULOSE PRODUCTS. 

PREPARATION OF CELLULOSE BY MEANS OF SODIUM SULPHITE. 

It has been previously mentioned that in preparing 
cellulose with caustic soda a portion of the latter may be 
replaced by sodium sulphate. This salt, to be sure, does 
not take part in the process, but when the used lyes are 
evaporated and the residue is heated, it is converted into 
sodium sulphite, which, like caustic soda, has a destructive 
effect upon the encrusting substance of the wood. Hence, 
in the course of the operation, before evaporating the used 
lyes, it is only necessary to add to them a determined 
quantity of sodium sulphate in order to obtain by the re- 
generation of the salt, the corresponding quantity of sodium 
sulphite. The highly evaporated lyes are mixed with 
limestone and coal-dust, and after drying, melted in a 
reverberatory furnace, whereby caustic soda and sodium 
sulphite are obtained. After washing the salts with water, 
they are dissolved and used for boiling. For every J 00 
parts of dry substance of the lye used, 100 parts of lime- 
stone and 25 parts of coal-dust are used. 

The further working of the washed cellulose is effected 
by purely mechanical means. As a rule, the pieces of 
cellulose, which still retain largely the form of the frag- 
ments of wood originally used, are ground in a mill with 
water to a paste. This paste is mixed with a large quan- 
tity of water and made homogeneous in the hollander. If 
to be used in the manufacture of finer qualities of paper it 
is also bleached with chlorine. The value of cellulose is 
the greater the longer its individual fibres are, because long 
fibres felt more completely together than short ones, the 
resulting paper being much stronger. However, generally 
speaking, finer qualities of paper are not made from wood 
cellulose alone, the pulp for them consisting, as a rule, of 
cellulose prepared from rags mixed with a certain per- 
centage of wood-cellulose. 



CELLULOSE FROM WOOD, OR CHEMICAL WOOD-PULP. 59 

The statements regarding the consumption of wood and 
chemicals in the different factories vary so much as to ren- 
der it difficult to give a correct idea of it. Moreover, the 
yield of cellulose appears to be essentially effected by the 
content of water in the wood to be worked. The content 
of water in thoroughly air-dry wood is about 20 per cent., 
while in many varieties of wood, when freshly cut, it may 
amount to twice as much, and for that reason the yield of 
cellulose will turn out quite different from that calculated 
from the weight of the wood. The nature of the wood to 
be worked is also of great influence upon the yield of fin- 
ished cellulose, as shown by the following figures given by 
Reid : 



Variety of wood. 


Cellulose in per cent. 


Length of fibre. 


Beech 


38.5 


short 


Birch 


42.0 


short 


Hemlock spruce 


37.5 


long 


Poplar 


41.7 


medium 


Pine 


39.0 


long 


Fir 


38.0 


long. 



PREPARATION OF CELLULOSE WITH THE ASSISTANCE OF SUL- 
PHITES, (sulphite-cellulose ACCORDING TO 

mitscherlich's process). 
Solutions of acid sulphites possess, similar to caustic alka- 
lies and their combinations with sulphur, the property of 
dissolving and destroying the encrusting substance of wood. 
The process of preparing cellulose in this manner is the in- 
vention of the German chemist Mitscherlich, all other sul- 
phite processes being more or less suitable modifications of 
it. In establishing a sulphite-cellulose plant it is of the 
utmost importance that an abundance of water should be 
available, and besides the conditions must be such that the 
waste liquor can be discharged into a water-conrSe of consid- 
erable size. For the manufacture of 4,400 lbs. of air-dry 
cellulose about 15,000 gallons of water are required, and 
the waste liquor of the plant must be diluted to such an 



60 CELLULOSE, AND CELLULOSE PRODUCTS. 

extent as not to be detrimental to the existence of animals 
in the streams into which it is discharged, since otherwise 
the unavoidable consequence would be that the plant 
would constantly have to pay large amounts for damages to 
the proprietors of the fishing rights in the respective 
streams, and might even be forced entirely to suspend 
operations. 

The wood has to be prepared with special care and 
should be used as soon as possible after having been cut 
down. In case wood which has been cut for some time is 
to be worked, it should previously be for a few days placed 
in water. Since there is a difference in the behavior of the 
various kinds of wood toward the sulphites, only one 
special variety should at one operation be worked. 

The trunks to be used must be carefully freed from bark 
and bast, and adhering dirt is to be removed, so that only 
perfectly clean wood is brought into the saw-mill. In the 
latter, the trunks are cut by circular saws into blocks about 
16 inches long, and the knots cut out by a suitable 
machine. Finally the blocks are cut up into thin discs not 
more than 1 inch thick, which are again inspected, pieces 
with knots in them being rejected. In preparing the wood 
in the manner above described there will naturally be con- 
siderable waste, and besides a large quantity of sawdust. 
The latter, to be sure, can be worked together with the 
discs, but readily causes annoyance and trouble by obstruct- 
ing pipes, etc. Hence, in many plants the practice of 
cutting the blocks into discs has been entirely abandoned, 
the blocks being converted by a machine resembling a 
planing machine, into thin boards 0.27 to 0.29 inch thick, 
an essential advantage of this procedure being that the 
longitudinal fibres of the wood are preserved and cellulose 
of greater length can be obtained. 

Pine is considered the best material for the preparation 
of sulphite cellulose, and next to it, fir is most highly 
valued. Scotch fir, to be sure, is also suitable for the pur- 



CELLULOSE PROM WOOD, OR CHEMICAL WOOD-PULP. 61 

pose, but only the sap-wood should be used, the heart 
yielding cellulose of a dark color. Other varieties of wood, 
including deciduous trees, may also be used, but the cellu- 
lose obtained from them is not as strong as that from coni- 
fers, and the yield of finished cellulose is small. 

The preparation of cellulose by the sulphite process may 
be divided into three principal operations : 
I. Preparation of the sulphite solution. 
II. Boiling the prepared wood with the solution. 

III. Treatment of the cellulose mass obtained. 

PREPARATION OP THE SULPHITE SOLUTION. 

According to Mitscherlich's process, the incrusting sub- 
stance of the wood is dissolved by the use of solution of 
calcium bisulphite, obtained by treating calcium carbonate 
with sulphurous acid. The operation is carried out as fol- 
lows : 

Sulphurous acid in gaseous form is conducted into a 
vessel filled with porous limestone, water being at the 
same time allowed to flow over the limestone. From the 
limestone, from which the carbonic acid has been expelled, 
neutral calcium sulphite is first formed. However, since 
sulphurous acid is present in excess, it ascends in the ves- 
sel, dissolves in the water trickling down and flows back 
over the neutral calcium sulphite, which, as it dissolves 
with greater difficulty than the limestone, has settled upon 
the latter. Calcium bisulphite, which dissolves with ease, 
is now formed, and the resulting solution of this salt runs 
off into a collecting reservoir. In cellulose plants this 
solution is briefly called lye, and by this term it will be 
referred to throughout the succeeding pages. 

Very large quantities of lye being required in a cellulose 
plant, the apparatus for its preparation must be of ade- 
quate size. In reference to this, Mitscherlich, who has 
worked out to the smallest details the entire operation of 
this process, makes the following important statements: 



62 CELLULOSE, AND CELLULOSE PRODUCTS. 

The limestone serving for the preparation of the lye 
should be as pure as possible, so that not too much niud is 
formed by foreign substances (magnesia or organic sub- 
stance) contained in it. It should further be very porous 
and at the same time firm, so as not to be crushed by the 
weight of the layer over it, which might cause troublesome 
obstructions in the apparatus. A material which can be 
recommended for the purpose is solid tufaceous limestone 
in pieces about the size of the fist, which are piled up to the 
height of 39.37 inches in the tower-like structure in which 
the lye is prepared. To prevent the pieces of limestone 
from packing too closely together and crumbling in falling 
down the entire height of the tower, the latter is filled to a 
certain depth, and a fresh charge equal in size to the orig- 
inal one is introduced from the top of the tower w^hen the 
layer of limestone has sunk to a certain depth. * 

The sulphurous acid required for the preparation of the 
lye is obtained by burning sulphur or, if cheaper, pyrites. 
Sulphur-burning is an operation requiring careful regula- 
tion, so that combustion is complete and no unburnt sul- 
phur reaches the absorbing tower. One of the best tests in 
this respect is the color of the flame, which should be pure 
blue. The appearance of a yellow, dark flame is an indi- 
cation of an insufficient admission of oxygen, the conse- 
quence of which is generally an evaporation of unburnt 
sulphur which may damage the pipes and become very 
troublesome. Incomplete combustion of the sulphur may 
be due to an inadequate supply of air to the furnace itself, 
but it may also be caused by the current of gas ascending 
in the absorbing tower not being strong enough, and hence 
the entire apparatus needs careful watching. In order to 
have, in addition to the appearance of the flame, a means 
of testing whether sulphur in the form of vapor is carried 
along with the sulphurous acid, a wide glass tube, /, Fig. 
,28, is inserted in the pipe through which the sulphurous 
acid is conducted, a portion of the latter passing through 



CELLULOSE FROM WOOD, OR CHEMICAL WOOD-PULP. (')3 




the glass tube, and the appearance of a 3'ellow tinge in the 
latter is an indication of a content of unburnt sulphur in 
the gas. The arrangement of the absorbing tower in which 
the formation of the lye takes place is shown 
in Figs. 24 and 25. The pipe through 
which the sulphurous acid is conducted 
from the furnace k should rise at least two- 
thirds the height of the tower, then turn 
downward at a right angle and enter the 
tower from below. The ascending portion 
a of this pipe is constructed of iron, while 
the descending portion b consists generally 
of tile-pipe. The nearly horizontal portion 
of the pipe through which the gas enters 
the tower must by all means consist of tile-pipe. The 
diameter of the pipe should be such that the gases are not 
exposed to considerable friction and may sufficientl}' cool 
off before entering the tower. 

The absorbing tower is 105 feet high and about 5 feet 
square. It is constructed of wood, very resinous wood, for 
instance, Scotch fir or pitch pine, being used. Larch being 
expensive is more seldom employed. The walls of the 
tower must be thick, the lower portion being made 3.15 
inches, the centre portion 2.36 inches and the upper portion 
1.57 inches thick. The separate i)arts of wood are held 
together by stout iron hoops secured by screws, they, as well 
as the screws, being carefully coated witb tnr. Joints be- 
tween the })arts of wood are stufted with tcnv and coated 
with tar. 

The lower poiiion of the tower is furnished with a grate h 
of oak beams, which must be strong enough to support the 
load of the layei- of limestone placed upon it. Between the 
grate beams are openings 2.5)5 inches wide through which 
the gases ascend and the lye runs flown. The upper faces 
of the beams are 2. 1^5 inches wide, but the lower ones only 
1.96 inches. Two oak beams are also placed in the tower 



64 CELLULOSE, AND CELLULOSE PKODUCTS. 

3i feet above the grate for tl,e purpose of partially relieving 
lit Boards placed horizontally are secured by 

Fi(i. 25. 




means of 



stout wooden pvgs to the walls of the tower at 



CELLULOSE PROM WOOD, OR CHEMICAL WOOD-PULP. 65 

distances of 3^ feet one above the other. These boards 
slope inward, so that the fluid dripping down upon them is 
conducted towards the interior of the tower and the walls 
of the latter are not moistened. Figs. 26 and 27 show on 
an enlarged scale the shape of these boards and the manner 
of fastening them. 

Large as such a tower is, it is scarcely of sufficient size 
to prepare in it the lye required for one boiler. In order 
to carry on operations without interruption and to be able 
occasionally to clean a tower which has been in use for a 



Fig. 26. 



Fig. 27. 





longer time, it would seem to be advisable to build four 
towers, erecting one on each corner of a square, and placing 
the stairs, water pipe and hoist for the limestone in the 
square. Reservoirs for the reception of the lye which is 
discharged through a lead pipe from the tower are located 
alongside the latter. The lead pipe is placed slightly above 
the bottom of the tower and is bent at a very obtuse angle 
like a siphon, thus forming a hydraulic joint which allows 
of the lye running ofl^, but prevents the escape of gas from 
the tower. The lye first passes through the lead pipe into 
a barrel open at the top and divided into two compartments 
by a partition reaching half-way up. The greater portion 
of the mud carried along by the fluid settles on the bottom 
5 



66 CELLULOSE, AND CELLULOSE PRODUCTS. 

of the barrel. From the bottom of this barrel the fluid 
passes through a lead pipe into an<^t]ier barrel filled with 
small pieces of limestone in which the small quantity of 
free sulphurous acid, which ma}' still be contained in the 
lye, is fixed. After passing through this barrel, the lye 
runs into the actual lye-reservoirs. 

Large, prismatic, wooden boxes, 16J feet wide, 10 feet 
deep and 23 feet long, serve for lye reservoirs, at least two 
of which should be provided for every boiler. The lye con- 
tained in one of these reservoirs being just sufficient for one 
boiling, the two reservoirs are connected by a wooden pipe 
so arranged that the connection can be cut off for the pur- 
pose of cleaning one reservoir while the latter is being filled. 
The conduits leading from the reservoirs to the boiler are 
also constructed of tarred wood, this material being more 
capable of resisting the action of the lye than all others, 
even not excepting lead. 

In preparing the lye care must be taken that the sulphur- 
ous acid obtained by combustion reaches the tower entirely 
cooled oflP. When the odor of sulphurous acid commences 
to be perceptible at the upper aperture of the tower, water 
is introduced from the reservoir m placed at a higher level, 
and the supply is so regulated that the odor of sulphurous 
acid can just be noticed, the object in view, namely, to ob- 
tain a lye as concentrated as possible being in this manner 
most assuredly attained. In case an irregularity should 
occur in the course of the operation, it is either due to the 
sulphurous acid carrying along with it vapors of sulphur, 
or the supply of water is too small, so that the neutral cal- 
cium sulphite formed upon the pieces of limestone cannot 
be converted into the readily-soluble acid combination, or, 
finally, it may be caused by the current " gas being ob- 
structed in the tower. In this case a remedy must at once 
be applied and an effort be made to overcome the disturb- 
ance by a stronger supply of water kept up for some time. 



CELLULOSE FROM WOOD, OR CHEMICAL WOOD-PULP. 67 
BOILING THE WOOD WITH THE LYE, 

The object of this operation is to bring into solution the 
encrusting substance and convert the wood into cellulose. 
For this purpose a large iron vessel or boiler of cylindrical 
shape, Figs. 28 and 29, is used, which is furnished with 
four manholes, two on top and two on the bottom. All the 
fixtures for the introduction of lye, steam, etc., are placed 
on the lids of the manholes, because they can be more 
readily kept tight there than in an}' other place. To pre- 
vent the lye from coming in direct contact with the iron, 
the latter being strongly attacked by it, the interior surface 
of the boiler is first coated with a mixture of pitch and 
common tar, the proportions of the mixture being such 

Fig. 28. 




that, when heated the coat is quite thinly-fluid^ but very 
sticky at the ordinary temperature. Upon this coat is laid 
a thin layer of sheet-lead, at least 0.07 inch thick, and 
rubbed down smoothly so that the interior surface of the 
boiler appears to be lined with lead. The portions of the 
boiler which have to be moved — the lids of the manholes, 
etc. — are prov' i with a double protecting covering of 
thicker sheet J. The interior space of the boiler is lined 
with brick k. as shown in Fig. 30. The brick used for 
the pur' should not be porous but of a porcelain-like 
riaturr Phe lower portion of the interior surface of the 



68 



CELLULOSE, AND CELLULOSE PRODUCTS. 



boiler is furDished with a double-brick lining, that in the 
upper portion being single. For the sake of a close joint, 
the bricks are grooved and tongued and the spaces between 
them filled with cement. Lining has to be done with the 



Fig. 29. 



Fig. 30. 





greatest care, and when testing the boiler in the cold up to 
six atmospheres no exudation of fluid should anywhere be 
perceptible. 

Heating of the mass in the boiler is effected by four sys- 
tems oi heating pipes — see Fig. 28, below to the left. The 
heating pipes are made of hard lead — an alloy of lead and 
antimony — and they have comparatively thick walls — 3.15 
to 3.18 inches. For a boiler 39 feet long and 13 feet in 
diameter, the pipes of each heating system must have a 
length of 656 feet, hence a total length of 2,624 feet is re- 
quired. The heating pipes are connected with the steam 
pipes and, on the places where they branch off from the 
latter, are provided with valves which prevent the lye from 
running into the boiler in case one of the pipes becomes 
defective. 

The proportion between wood and lye is as follows : The 
Ij'^e should have a concentration of 7° B^., and for every 
70.62 cubic feet of boiler space 35.31 cubic feet of pine 
wood, together with the sawdust belonging to it, are used. 



CELLULOSE FROM WOOD, OR CHEMICAL WOOD-PULP. 69 

If weaker lyes are employed, the quantity of wood has to 
be correspondingly decreased ; thus, for instance, with lye 
of 6°, one-seventh less the quantity of wood is taken. The 
wood and sawdust are as uniformly as possible distributed 
in the boiler, the latter being filled one-quarter full of 
wood, and the sawdust is distributed in piles upon the wood. 

When the boiler has been filled with wood, the lids of 
the manholes are placed in position and their joints luted 
with a thick cellulose paste. The safety-valve is then re- 
lieved and the valves on the lower portion of the boiler are 
slightly opened. Steam is then introduced into the boiler 
in such a way that a very slight jet of it passes out of the 
lower valves, the object of this operation being to moisten 
the wood uniformly and to expel the air from its pores. 
In working dry wood, the steam is allowed to pass through 
the boiler up to ten hours, but for wood freshly cut and 
containing even considerable moisture, a much shorter time 
is required. When, after steaming is finished, the cold lye 
is allowed to run into the boiler, the steam in the pores of 
the wood is condensed and the lye penetrates quickly into 
the interior of the blocks of wood. 

Immediately after the introduction of steam has been 
interrupted and the valves have been closed, the valve con- 
necting the boiler with the lye reservoir is opened, and in 
consequence of the vacuum thus created in the boiler the 
lye runs rapidly into the latter. Steam is now continuously 
introduced through the system of heating pipes, so that the 
contents of the boiler are as rapidly as possible brought to 
a temperature of 230° F., this temperature being main- 
tained as uniformly as possible for twelve hours, when it is 
gradually raised to 242.6° F. 

When the temperature has reached 230° F. a series of 
tests are made to see how much effective calcium bisulphite 
is still present. The test is executed as follows : A glass 
tube about 7| inches long is suspended to a vertical stand 
which is furnished with marks indicating |, f^, 3V of the 



70 CELLULOSE, AND CELLULOSE PRODUCTS. 

volume content of the glass tube. Ammonia is now intro- 
duced into the glass tube up to the gV mark, and the tube 
is then almost entirely filled with hot lye drawn from the 
boiler. The glass tube is then closed and ammonia and lye 
mixed by vigorous shaking. The glass tube is then sus- 
pended to the stand and in a few minutes a precipitate is 
formed, the semi-fixed sulphurous acid being neutralized b}' 
the ammonia, while calcium sulphite, which is soluble with 
difficulty, is separated as a precipitate. From the precipi- 
tate the proportion of the effective solution can be readily 
determined. When the precipitate is only equal to one- 
sixteenth of the length of the glass tube, boiling is nearly 
complete. When the precipitate is only equal to one- 
thirty-second, heating is immediately interrupted and the 
boiler emptied. A very rapid decrease in the precipitate 
towards the end of boiling is an indication of detrimental 
processes taking place in the boiler. When the lye in con- 
sequence of having been improperly prepared contains poly- 
thionic acids, a modification of the process in the boiler 
takes place, the calcium sulphite being then decomposed 
and calcium sulphate (gypsum) and sulphur are separated 
upon the wood. The wood remains brown and hard, and 
is not completely converted into cellulose. 

When the operation is properly conducted, boiling is 
finished in from 36 to 48 hours. 

For the purpose of regaining the sulphurous acid, an 
abundance of which is still contained in the lye after the 
operation, the lye is allowed to enter a lead coil which lies 
in a cooling vat and terminates in one of the towers. In 
the lead coil the water which is saturated with sulphurous 
acid is condensed and collected by itself, while the sulphur- 
ous acid passes into the tower, to be again used for the 
preparation of lye. 

WASHING THE CELLULOSE. 

When boiling has been finished, the contents of the 



CELLULOSE FROM WOOD, OR CHEMICAL WOOD-PULP. 71 

boiler are emptied into a receptacle underneath the boiler, 
and after the cellulose-mass has settled to the bottom, the 
supernatant fluid is discharged into a watercourse, provided 
it is in a highly diluted state. If this, however, is not the 
case, the fluid has to be mixed with a quantity of milk of 
lime sufficient for the conversion of the calcium bisulphite 
and the free sulphurous acid still contained in it, into cal- 
cium sulphite, which settles on the bottom of the receptacle 
and may be again converted into calcium bisulphite by the 
introduction of sulphurous acid into the water poured 
over it. 

When the boiler has been emptied it is rinsed out with 
water, and before starting a fresh operation, it is advisable 
to subject it to a thorough examination and to knock off 
with a wooden mallet any gypsum which may have de- 
posited on the brick work. 

The cellulose-mass coming from the boiler contains cer- 
tain quantities of finely divided gypsum, fragments of 
neutral calcium sulphite, and besides is saturated with lye. 
To free it from these admixtures it is subjected to the action 
of a stamping mill, the operation being assisted by large 
quantities of water. The cellulose-mass is directly con- 
veyed by a transporting contrivance from the boiler to a 
funnel from which it falls into the stamping trough, in 
which, mixed with the proper quantity of water, it is sub- 
jected to the action of the stamps. The latter are so set 
that they cannot fall entirely to the bottom of the trough, 
crushing the mass being thus prevented. From the stamp- 
ing mill the pasty mass runs off through broad gutters 
which are provided with sand-catchers for keeping back 
sand, grains of gypsum, etc., the particles floating on the 
top being retained by a cleaner placed over the fluid. 
From the gutters the pulp reaches an inclined cylinder 
covered with a wire sieve. The water runs off through the 
meshes of the sieve, while the cellulose in the form of 
crumbs leaves the cylinder at the lower end and is quite 
completely freed from moisture by rolls. 



72 CELLULOSE, AND CELLULOSE PRODUCTS. 

DEFECTS OF CELLULOSE AND THEIR REMOVAL. 

Owing to deviations from the proper process of working, 
the finished cellulose may show various defects which may 
partially be remedied. According to Mitscherlich the 
most important defects are as follows : 

The cellulose instead of being pure white shows a yellow- 
ish or brownish color. The cause of this phenomenon is 
due to the fact that towards the end of boiling the required 
quantity of sodium bisulphite was no longer present. Such 
cellulose can be made quite white by bleaching with chlorine. 

Some white pieces not converted into fibre may occur in 
the otherwise uniform mass, which is an indication of too 
much wood having been brought into the boiler. Such 
cellulose may very well be used for the manufacture of firm 
and strong paper, but must first be carefully rolled. How- 
ever, such cellulose is less suitable for bleaching. 

The occurrence of black particles in the mass is gen- 
erally due to insufiicient cleaning of the wood before it is 
cut up, and is caused b}' rotten pieces of bark which have 
been left on the wood. The black spots may also be due to 
particles of the belts, this being a defect which cannot be 
removed. Some kinds of cellulose contain small, soft 
bundles of fibre of a brownish color which may have been 
caused by the respective particles having become too hot in 
the boiler, or by incompletely freeing the wood from bast. 
These defects, as a rule, disappear completely by subjecting 
the cellulose to bleaching with chlorine. 

The occurrence of larger brown bundles of fibre of con- 
siderable firmness is mostly due to a gross error committed 
in boiling, or to the fact that some of the stamps of the 
stamping-mill have come too near to the trough. With the 
use of the proper quantity of water and a right width of the 
slits in the splinter-catcher, these pieces should have been 
retained during washing. 

With the microscope small, lustrous crystals may some- 



CELLULOSE FROM WOOD, OR CHEMICAL WOOD-PULP. 73 

times be noticed in the cellulose, this being proof of an in- 
sufficient quantity of water having been used in washing. 

If the microscope shows the presence of small particles of 
an earthy appearance it is an indication of too little wood 
having been used in boiling, these particles consisting of 
neutral calcium sulphite. They can be most readily re- 
moved by an addition of hydrochloric acid to the wash- 
water, but cellulose thus treated requires a larger quantity 
of chlorine in bleaching. A change in color of the at first 
pure-white cellulose during washing is due to small quanti- 
ties of iron which reach the mass chiefly through the wash- 
water and iron utensils. This iron may also be removed 
by acidulating the wash-water with hydrochloric acid. 

The finished cellulose may either be immediately used 
for the manufacture of paper, or it may be freed from the 
larger portion of water by pressure. If, however, it is to 
be kept without undergoing a change, it has to be com- 
pletely dried, as otherwise it becomes readily mildewed, 
especially when exposed to heat. 

Other methods for the manufacture of cellulose by the 
sulphite process differ in details only from Mitscherlich's 
process above described, all being based upon the proposi- 
tion that by boiling wood under an increased pressure with 
solution of calcium bisulphite the encrusting substance is 
dissolved and the mass need only be thoroughly washed to 
yield a material available for the manufacture of paper. 

PREPARATION OF CELLULOSE WITH THE ASSISTANCE OF THE 
ELECTRIC CURRENT. KELLNER's PROCESS. 

This process diff'ers essentially from the methods pre- 
viously described, and is based upon a very ingenious ap- 
plication of the electric current, the latter being used for 
decomposing common salt solution. When an electric cur- 
rent of suitable strength is allowed to act upon a solution of 
sodium chloride (common salt), caustic soda, free chlorine 



74 



CELLULOSE, AND CELLULOSE PRODUCTS. 



and hypochlorous acid are formed. By allowing these 
bodies to act alternately at a suitable temperature upon 
wood, the lignin will in a certain time be completely de- 
stroyed and pure cellulose remain behind. 

For carrying out his process, Kellner uses the apparatus, 
shown in Fig. 31, consisting of three boiling vessels B, A 
and L, which are connected one with the other by the pipes 
H, J, M, TV and K, the positive pole of a source of electricity 




(a dynamo) entering at R and the negative pole at S. When 
the apparatus is to be used, the boilers A and B are charged 
through the manholes E with wood prepared in the usual 
manner, and common salt solution is then allowed to run in 
until it becomes visible in the fluid-indicator L which is 
located in the interrji^iiary boiler. Coils of pipe through 
which high-pressure steam is conducted lie in the boilers 
A and B. Heating is continued until the temperature of 



CELLULOSE FROM WOOD, OR CHEMICAL WOOD-PULP. 75 

the common salt solution has been brought to 262.4° F., 
when the electric current is closed, whereby the common 
salt solution is decomposed, caustic soda, free chlorine and 
hypochlorous acid being formed. The fluids containing 
these bodies ascend from M and N through J J, act upon 
the wood contained in A and B, and reunite in the vessel 
L. The gases accumulating in L are conducted through 
the valve V and the pipe T into the condenser P. 

As will be seen from the above description, the wood in 
one of the boilers is treated with caustic soda lye and that 
in the other with chlorine and hypochlorous acid, both of 
these bodies having a destructive effect upon the encrusting 
substance. To make the process entirely uniform, the 
direction of the electric current is from time to time re- 
versed, so that the wood which has been treated with 
caustic soda is exposed to the action of the chlorine and 
vice versa. 

By reason of the powerful chemical action of the caustic 
soda and chlorine alternately exerted at short intervals 
upon the wood, the operation proceeds with greater rapidity 
and smoothness than by any other method, and cellulose in 
a perfectly bleached state is directly obtained from the 
apparatus. These advantages should certainly be sufficient 
to insure to Kellner's process extended application in prac- 
tice. 

PREPARATION OP CELLULOSE PROM STRAW. 

While all efforts to prepare from the straw of our varieties 
of grain a cellulose suitable for the manufacture of finer 
qualities of paper were for a long time in vain, recent en- 
deavors in this direction have been crowned with success, 
and this material is now worked on a large scale by several 
factories. In working straw for cellulose, the preparatory 
operations form a very important part of the process. The 
straw has not only to be freed from adhering earth, weeds, 
etc., but also as far as possible from the knots of the indi- 



76 CELLULOSE, AND CELLULOSE PRODUCTS. 

vidual stalks, these knots offering far greater resistance to 
the action of the chemicals than the tubular portions. 

The operation is commenced by opening the bundles of 
straw and shaking out the weeds as much as possible. The 
straw is then cut very fine in a straw-cutter and cleaned by 
means of a fan. The current of air in the latter should be 
of such a force that the particles of stalks are positively 
carried away, while the heavier bodies, including the knot- 
pieces, fall to the bottom. If the operation is properly 
carried on, the greater portion of the knot-pieces, as well 
as the grain still contained in the straw, will be found in 
the mass collected in front of the fan, while the cut straw 
which has been blown away consists chiefly only of tubular 
particles of stalks. 

For the further working of the winnowed straw the soda 
process is generally used, the encrusting substance of the 
straw being much more readily dissolved in the alkaline 
fluid than that of wood. Hence, boiling may be effected 
under considerably less pressure, three to, at the utmost 
five, atmospheres being in most cases sufficient. 

The great volume occupied by the finely-cut straw is an 
objectionable feature which might necessitate the employ- 
ment of boilers of very large dimensions. This may, how- 
ever, be overcome by pressing down the straw in the boiler, 
while the lye is allowed to enter from below. By the action 
of the lye the bulk of the straw is very rapidly decreased 
and 1,100 pounds of straw can in this manner be readily 
worked at one time. 

Horizontal cylindrical boilers of the revolving type have 
been found most suitable for working straw. The boiler 
having in the above-mentioned manner been filled with 
straw and lye, a portion of the latter is discharged, so that 
the boiler is only one-third full of lye. Steam is then in- 
troduced through the hollow trunnions of the boiler and 
the latter is made to revolve slowly — once in one or two 
minutes — around its axis. By boiling, the straw is con- 



CELLULOSE FROM V'OUxy, OR CHEMICAL WOOD-PULP. 77" 

verted into a pasty mass, and boiling has to be continued 
until samples taken from the boiler show the complete dis- 
integration of the knotty particles. 

The boiler is then placed so that the man-hole is turned 
downward, and the pasty contents are allowed to run out. 
Since the individual particles adhere together in the form 
of fibres, the entire mass is passed through a stuff-mill 
consisting of a stationary bed-stone and a revolving runner. 

Since the characteristic yellow coloring-matter of the 
straw is not decomposed by boiling with the alkali, the re- 
sulting cellulose would also be of a yellow color, and hence 
the mass has to be bleached. Before this is done, it must, 
however, be completely freed from alkali by washing, 
special apparatus being employed for this purpose. 

Bleaching by means of chloride of lime is effected in the 
hollander, 11 to 22 pounds of chloride of lime being re- 
quired for every 220 pounds of dry straw. During the 
process of bleaching, the mass must be kept in constant 
motion, and the operation should be effected at the ordinary 
temperature, since at an increased heat, the cellulose itself 
would be attacked by the chlorine and carbonic acid be 
evolved from the mass. The treatment with chloride of 
lime must be succeeded by thorough washing and, in case 
the finished product is not to be immediately used for the 
manufacture of paper, it has to be freed from water by 
hydraulic presses. 

According to different statements, the yield of finished 
cellulose varies very much, but it appears to be chiefly de- 
pendent on the state of maturity of the straw used. From 
all that can be learned on the subject, a yield of 72.6 to 88 
pounds of dry cellulose from every 220 pounds of straw used 
may be calculated on. 

Besides the straw of the different varieties of grain, other 
parts of plants are utilized for the preparation of cellulose 
for the manufacture of paper, esparto (from Stipa tenacissima) 
especially being largely employed in England for that 



78 CELLULOSE, AND CELLULOSE PRODUCTS. 

purpose. The leaves of the esparto plant present the ad- 
vantage of being very readily disintegrated, an increase in 
the pressure during boiling not even appearing necessary. 
The cellulose obtained from esparto is said to be distin- 
guished by great firmness and pliability, so that it is suit- 
able for the manufacture of very firm, white writing-papers. 
The quantitative yield also is said to be very satisfactory, 
92.4 to 110 pounds of cellulose being obtained from 220 
pounds of raw material. 

Jute bagging, which has been used for shipping trans- 
atlantic products, is also utilized, when it can be had in 
sufficient quantities, for the preparation of cellulose, and 
this cellulose is especially suitable for the imitation of gen- 
uine Manila paper which is prepared from the fibres of 
Manila hemp, Musa textilis. The first step in working jute 
in the form of cuttings or " butts," spinner's waste and 
bagging, is to cut up the material in a rag-cutting machine. 
The comminuted mass is then brought into a rag-boiler 
and for some time boiled under slight pressure — 1| atmos- 
pheres — with a comparatively large quantity of lime — 
25 to 35 per cent, of the weight of the jute. It is then 
washed in a half-stuff hollander and ground. As a rule, it 
is finally slightly bleached with chloride of lime. 

UTILIZATION OF EXHAUSTED LYES AND THEIR 
NEUTRALIZATION. 

The fluids which have served for the preparation of 
cellulose from wood contain, in addition to a consider- 
able quantity of organic substance, the total quantity of 
mineral substances employed in their preparation. Partly 
for economic, and partly for hygienic, reasons, these sub- 
stances have either to be reconverted into such products as 
can be again utilized in succeeding operations, or it must 
be endeavored to change them in such a manner that they 
(Hiay, without risk, be discharged into a natural water- 
course, river or creek. 



CELLULOSE FROM Wuui/, vji. CHENIICAL WOOD-PULP. 79 

When working with the soda process, efforts are generally 
made to recover the soda as lar as possible. The exhausted 
lyes contain the soda largely in the form of organic com- 
binations which can be broken up by heat, carbonate of 
soda remaining finally behind, which may be again used 
for the preparation of lye. In order to recover the soda, 
the exhausted lyes are evaporated to dryness, and the re- 
sulting solid mass is calcined under the access of a strong 
current of air. The organic substance is thereby completely 
destroyed, the residue consisting of calcined (anhydrous) 
soda. 

Since the evaporation of such large quantities of fluid as 
-result in the manufacture of cellulose, requires a consider- 
able amount of fuel, the apparatus- used for the purpose 
should be so constructed as to allow of the heat produced 
being utilized to the fullest extent. Numerous propositions 
having more or less the object in view, namely, the saving 
of fuel, have from time to time been made. However, 
reverberatory furnaces are most frequently used for calcining 
the evaporated mass, the still very hot fire gases escaping 
from the furnace being utilized for heating shallow pans 
in which the lyes are constantly more and more concen- 
trated, and finally converted into a solid mass ready for 
calcination in the furnace. 

The quantity of soda recovered is of course considerably 
smaller than that originally used, a portion of it having 
been lost in the wash waters, but the latter do not contain 
enough of it to make their evaporation profitable. How- 
ever, if the operation is properly conducted, from 60 to 66 
per cent, of the soda used may be recovered. When work- 
ing with the sulphite process, it is of the utmost importance 
to change the lyes so as to be able to discharge them, with- 
out risk, into running water. According to Mitscherlich, 
this is to be effected by greatly diluting the lyes, as well as 
the water used in washing the cellulose. However, it must 
be borne in mind that very large quantities of exhausted 



80 CELLULOSE, AND CELLULOSE PRODUCTS. 

lye are daily produced in a cellulose plant. Every quart 
of exhausted sulphite lye contains, in round numbers, 3 
ounces of organic substance in solution and, in addition, 
the total quantity of mineral substances contained in the 
original lye. 

However, since the lyes contain considerable quantities 
of sulphites which become decomposed in water, sulphur- 
etted hydrogen being evolved, it will be readily understood 
that the waters of even a quite considerable stream will, in 
the course of time, become polluted to such an extent as to 
kill the fish inhabiting them, sulphuretted hydrogen being 
an exceedingly violent poison for them. 

It would, therefore, seem absolutely necessary to neutral- 
ize the lyes as much as possible before discharging them 
into a water-course. According to a process proposed for 
this purpose by A. Frank, the exhausted lye from a boiling 
is mixed in a large cistern with a sufficient quantity of 
milk of lime to form neutral calcium sulphite which, being a 
salt that dissolves with difficulty, settles to the bottom, and 
after having been freed as far as possible from the fluid in 
a filter-press, can be re-used for the preparation of sulphite 
lye. The fluid having been separated from the neutral 
calcium sulphite is freed in another receptacle from the ex- 
cess of lime by the introduction of smoke gases containing 
much carbonic acid, while the oxidation of a considerable 
quantity of organic substance is effected by conducting 
compressed air through the fluid. The fluid thus far puri- 
fied is conducted upon an irrigation field and, after re- 
maining there for some time, is discharged into running 
water. The calcium sulphite thus regained covers a con- 
siderable portion of the expense incurred in carrying out 
the process. 

The sulphite lyes may also be utilized in tanning, but 
being of a very dark color, they impart this color to the 
leather, and besides make it brittle. However, this draw- 
back may be overcome, and, according to a process proposed 



CELLULOSE FROM WOOD, OR CHEMICAL WOOD-PULP. 81 

by Honig, the lye, previous to being concentrated by evap- 
oration, is deprived of its color by treating it with zinc 
dust and sulphuric acid, a sufficient quantity of the latter 
to decompose all the sulphites contained in the fluid being 
required. 

In carrying out this process, the resulting large quanti- 
ties of sulphurous acid may, of course, be utilized for the 
preparation of fresh lye, a portion of the expense incurred 
being thereby covered. 
6 



VEGETABLE PARCHMENT. 

When unsized paper, which should, however, contain no 
wood-pulp, is for a short time subjected to the action of 
quite concentrated sulphuric acid, the cellulose undergoes 
a peculiar physical change. The paper loses considerably 
in thickness, assumes a transparent appearance, becomes 
harder and acquires a condition reminding one of horn, be- 
coming at the same time about five times as tenacious as 
the original material. AVhen paper thus treated is moist- 
ened, it loses its rigidity and acquires the condition of 
animal bladder. If stretched tight and allowed to dry, it 
regains its former horn-like condition. The chemical com- 
position of vegetable parchment is exactly the same as that 
of cellulose and, hence, the change effected by parchment- 
izing in the above-described manner is simply a physical 
one. Concentrated solution of zinc chloride produces the 
same parchmentizing effect as sulphuric acid, but in prac- 
tice this process is not used, because it is far more expensive, 
and the complete removal of the poisonous zinc salt is far 
more troublesome than that of sulphuric acid. 

The parchmentizing action of sulphuric acid is explained 
as follows : A solution of cellulose in concentrated sulphuric 
acid is first formed to a certain depth upon the surface of 
the paper, but so soon as the latter is taken from the sul- 
phuric acid and brought in contact with a large quantity 
of water, the solution is immediately decomposed to free 
sulphuric acid and amyloid, the latter cementing the indi- 
vidual cellulose fibres together to a uniform mass. By this 

(82) 



VEGETABLE PAE.CHMEXT. bo 

cementation the paper acquires its extraordinary strength 
and transparent appearance. 

NATURE OP THE PAPER TO BE PARCHMENTIZED. 

For the production of vegetable parchment of the proper 
quality, paper especially made for this purpose has to be 
used, it being of the utmost importance that it should not 
contain a filling stuff of any kind, and that it consists of 
nothing else but cellulose. It must, therefore, neither be 
sized nor contain an addition of a foreign body. 

In manufacturing paper intended for parchmentizing it 
has to be taken into consideration that its bulk is consider- 
ably decreased by the process, and hence it has to be made 
of sufficient thickness. To make the process of parchment- 
izing effectual, it is necessary for the paper to become com- 
pletely impregnated with the acid the moment it comes in 
contact Avith it, it being only under tliese conditions that 
the momentary solution of the cellulose in the sulphuric 
acid takes place, not only upon the sui face, but also thi'ough^ 
out the entire bulk, of the paper. Hence paper to answer 
these requirements must, on the one hand, bo of suitable 
thickness, and, on the other, should not be subjected to 
great pressure in passing through between the rolls. In 
this manner a loose, spongy paper is obtained, Avhicli is of 
comparativel}' little value for other purposes, but by reason 
of its porous, felt-like nature is especially well adapted for 
the preparation of vegetable parchment. 

As previously mentioned, by bringing paper in contact 
with sulphuric acid an actual solution of cellulose in the 
acid takes place, which must, however, be again rapidly 
decomposed. This fact renders it impossible to impregnate 
the paper throughout its entire bulk when the latter exceeds 
a certain limit, because before the acid could penetrate into 
the interior, a comparatively thick layer on the surface 
would be completely dissolved. However, if parchment of 
greater thickness is to be prepared, recourse may be had to 



84 CELLULOSE, AND CELLULOSE PRODUCTS. 

a process which is based upon the fact that paper just parch- 
mentized is very stick}' when taken from the sulphuric acid 
bath. Two, three, or even four, breadths of paper are 
simultaneously subjected — each by itself — to the action of 
the sulphuric acid, and when taken from the latter are 
passed together — one on top of the other — between rolls, 
whereb}'^, on the one hand, a considerable portion of adher- 
ing acid is squeezed out, and, on the other, the breadths of 
paper are inseparably cemented together. 

SULPHURIC ACID USED FOR PARCHMENTIZING. 

In order to obtain parchment of always the same quality, 
sulphuric acid of the same concentration and temperature 
has to be employed, and allowed to act upon the paper for 
a certain time. While the first-mentioned factors can be 
readily ascertained, the time during which the acid has to 
act depends largely on practical experience, and has to be 
fixed for every kind of paper by a few experiments on a 
small scale. Sulphuric acid of a specific gravity between 
1.659 (58° Be.) and 1.754 (63° B4.) has, after many experi- 
ments, proved most suitable for use. Larger quantities of 
a fluid of the desired concentration are at one time prepared 
by mixing concentrated sulphuric acid with water, the 
mixture being allowed to stand by itself until its temper- 
ature is reduced to at least 60° F., because acid of a higher 
temperature acts too energetically upon the paper, and the 
latter might in consequence be readily converted into a 
slimy mass. Many manufacturers prefer even to work with 
acid of quite a low temperature because all the operations 
can then be carried on more leisurely. 

The mixing of larger quantities of sulphuric acid with 
water being disagreeable work requiring great precaution, 
most of the manufacturers of parchment paper work with so- 
called chamber acid, which has a specific gravity in round 
numbers of 60° B^., and can be directly used, besides being 
considerably cheaper than highly concentrated sulphuric 
acid. 



VEGETABLE PARCHMENT. 85 

When working with acid of G0° B^., at a temperature 
not exceeding 60° F., five seconds' contact with the acid 
suffice for parchmentizing thinner varieties of paper. 
Thicker papers require a correspondingly longer time, and 
very thick papers are passed through the acid reservoir so 
slowly as to remain submerged upwards of 20 seconds. 

It must, however, be borne in mind that by coming in 
contact with the paper, the acid in the parchmentizing ves- 
sel becomes slightly heated, and hence to prevent it from 
acting too energetically upon the paper, the velocity with 
which the latter is drawn through the acid has to be some- 
what increased after the operation has for a short time been 
in progress. 

When the paper has remained the required time in the 
acid it is as rapidly as possible withdrawn from the action 
of the latter, this being effected by bringing it in contact 
with large quantities of water, by which the acid is diluted 
to such an extent that the cellulose is no longer affected by 
it. The last remnants of sulphuric acid adhering to the 
parchment are removed by treatment with an alkaline fluid. 

PARCHMENTIZING APPARATUS. 

For the manufacture of parchment paper on a large scale, 
an apparatus is used, the essential features of which are as 
follows : The endless paper to be worked is wound on a roll 
from which it can be smoothly unrolled under a slight pull, 
and is next carried under glass rolls beneath the surface of 
the sulphuric acid, the latter being contained in a lead- 
lined trough. By arranging several rolls in the trough the 
paper is for a suitable time exposed to action of the acid, 
and is finally lifted from it in a perpendicular direction. 
As soon as it appears above the lev^l of the fluid it is car- 
ried through between two rolls with sufficient pressure for 
the greater portion of acid to fall back into the lead-lined 
trough. The paper is now carried over glass rolls into a 
long trough filled with clean water, in which the greater 



8G CELLULOSE, AND CELLULOSE PEODUCTS. 

portion of still adhering acid is rinsed off. Since this first 
wash water becomes highly heated, it is advisable to charge 
the trough at the start with very cold water. From the first 
trough the paper reaches another one, in which it is further 
treated with water, it being best to have the water in this 
trough constantly running in a direction counter to that of 
the paper. This water absorbs but a very small quantity of 
sulphuric acid from the paper, and is allowed to run off 
from the wash-trough. It is advisable to sprinkle both 
sides of the paper, as it rises from the second trough, with 
fine jets of water from two horizontal pipes. 

The last traces of acid still adhering to the paper are 
removed by passing it through a trough filled with water, 
which is constantly kept alkaline by small quantities of 
caustic soda lye or ammonia. After again being treated 
with clean water the paper is subjected to strong pressure 
between rubber rolls or wooden rolls covered with felt. It 
then passes between adjusting rolls, and finally reaches 
hollow iron rolls heated by steam for the purpose of drying 
the finished parchment. 

While drying, the parchment has to be subjected to strong 
tension both lengthways and laterally, otherwise it would 
contract very much and acquire an uneven and wrinkled 
surface. 

Since the sulphuric acid used in the preparation of 
parchment is only highly diluted, without being otherwise 
changed, provision should be made for its recovery. This 
can best be effected by having the first w^ash-trough into 
which the paper passes directly from the sulphuric acid vat, 
of but a small size and furnishing it with a large discharge 
valve, as well as with quite a large water-supply pipe. 
Two horizontal sprinkling pipes are also fixed over this 
trough. 

"When the content of acid in the first wash water has 
increased to such an extent as to amount to 20 per cent, of 
the entire quantity of fluid, the discharge valve and the 



VEGETABLE PARCHMENT. 87, 

sprinkling pipes are opened. The contents of the trough 
run off in a few seconds, the acid being during this time 
washed from the paper by the sprinkling pipes. When the 
trough is empty, the discharge valve is immediately closed 
and the trough refilled with water by opening the cock of 
the large water pipe, the sprinkling pipes being finally 
closed. With a small-sized trough, a large valve, and a 
water pipe of considerable diameter, the discharge of the 
very acid water, as well as the refilling of the trough is so 
rapidly effected that the supply of water furnished during 
this time by the action of the sprinkling pipes is sufficient 
and the operation need not be stopped, and thus very 
large rolls of endless paper can, without interruption, be 
made into parchment. 

The wash water from the first trougli when it contains 
about 20 per cent, of sulphuric acid, can be readily worked 
to sulphuric acid of 60° Be., it being only necessary to 
evaporate it in a shallow lead pan heated by steam till the 
acid has acquired its ordinary concentration. When work- 
ing with the more concentrated commercial sulphuric acid, 
the wash water is utilized in place of pure water, for dilut- 
ing the acid. However, as in this case, an excess of sul- 
phuric acid would before long accumulate in the factory, it 
is advisable to use, instead of ordinary commercial acid, 
fuming sulphuric acid, the latter by reason of its content of 
sulphur trioxide requiring much more water for dilution to 
G0° Be. 

PROPERTIES OP PARCHMENT PAPER. 

By the conversion of ordinary paper into parchment its 
bulk is considerably decreased as well as its content of ash, 
but its specific gravity is much increased. The principal 
feature, however, is the increase in absolute strength, which 
makes parchment especially suitable for book bindings and 
all other purposes for which strength is a requisite. The 
changes paper undergoes by parch mentizing are shown for 
three different varieties of it, in the table below : 



88 



CELLULOSE, AND CELLULOSE PRODUCTS. 



Raw paper . 
Parchment paper. 

Eaw paper 
Parchment paper. 

Raw paper . . . 
Parchment paper. 



Thickness 
milli- 
meters. 


Specific 
gravity. 


0.234 
0.152 

0.178 
0.113 

0.134 
0.088 


0.617 
0.964 

0.543 
0.937 

0.624 
0.927 



Absolute 

strength 

per square 

millimeter 

Kilogrammes. 



1.415 

6.436 

1.483 
5.111 

1.503 

5.777 



Content of 
moisture 
per cent. 



6.785 
8.778 

7 071 

8.483 

6.978 
9.160 



Content 
of ash. 



633 
0.496 

0.645 
0.458 

0.678 
0.559 



As previously mentioned, the preparation of parchment 
of special thickness presents some obstacles, it being diffi- 
cult to saturate in a short time thick paper with sulphuric 
acid and to remove the latter rapidly. In this case two or 
more breadths of paper are treated, each by itself, with 
sulphuric acid and the first wash water, and then passed 
together, under quite heavy pressure, between rolls. T-je 
surfaces of the breadths of paper are at this time still suffi- 
ciently sticky to make it possible to combine the breadths 
so intimately to a single one, that the joint cannot be seen 
even by examining the cross section of the dried parchment 
with the microscope. By the use of an apparatus of suit- 
able construction, as many as four breadths may thus be 
combined in one and, though the thickness of the latter 
does not exceed that of ordinary drawing paper, its strength 
is actually surprising. Particular care must be taken in 
washing parchment of such special thickness, as it would in 
a short time be decomposed if a small quantity of sulphuric 
acid should happen to remain in its interior. 



RENDERING PARCHMENT PAPER FLEXIBLE. 

If parchment paper is to be deprived of its characteristic 
stiffness and hardness and to be rendered flexible, the object 
may be attained by suitable treatment with strongly hy- 



VEGETABLE PARCHMENT, 89 

groscopic bodies, glycerin being especially adapted for the 
purpose, as it is perfectly harmless and there can be no 
objection to the use of a material treated with it, for wrap- 
ping up articles of food. Parchment not intended for the 
latter purpose may be rendered flexible by the use of a con- 
centrated solution of magnesium chloride, calcium chloride 
or of another highly hygroscopic salt. The operation is 
carried on as follows : The finished parchment, before it 
has been dried, is allowed to run over a roll dipping par- 
tially into a vessel containing concentrated glycerin, a thin 
layer of the latter, regulated by a scraper, adhering to the 
roll and being transferred to the parchment. Parchment 
thus treated does not contract very much in drying and 
remains flexible to a certain degree. 

By reason of its great density parchment paper is easily 
colored, the separation of the coloring matter in it being 
readily efi^ected by placing it in a suitable solution. Ani- 
line colors are generally employed, fuchsin being used for 
r* d. The alcoholic solution of fuchsin is poured into boil- 
ing water and when thoroughly distributed in it, the parch- 
ment is introduced. For blue, water-soluble blue or indigo 
carmine is used ; for violet, aniline-violet, or the parchment 
is first colored red and then blue. Yellow is obtained with 
picric acid ; orange, with fuchsin and picric acid ; and green, 
with picric acid and indigo-carmine. 

The behavior of vegetable parchment towards the ordi- 
nary adhesive agents, such as mucilage, paste, glue, etc., is 
very unfavorable, they either do not adhere at all or crack 
off very readily. A somewhat better adhesion is effected by 
first applying alcohol, and then the adhesive agent to the 
parts of the parchment to be joined together, or by laying 
a strip of very thin ordinary paper between them. The 
best material for the purpose of joining together parchment 
paper is chromium glue, prepared by allowing glue to swell 
up in water to w^hich a quantity of potassium dichromate 
equal to 2 per cent, of the weight of the dry glue has been 



90 CELLULOSE, AND CELLULOSE PRODUCTS. 

added. When swelled up, the glue is dissolved by heating 
in water, the solution being kept in the dark until used. 
Chromium glue is used b}' coating the pieces to be joined 
with the solution, pressing them together and exposing 
them to the light, the chromium glue being thereby con- 
verted into an insoluble combination which onl}' swells up, 
without, however, dissolving if brought, even for a longer 
time, in contact with water. 

Vegetable parchment finds many applications. It is 
made into very strong pads for certain important writings, 
is employed for the manufacture of receptacles for articles of 
food, for instance, sausage casings, further for durable book 
bindings, etc., and large quantities of it are also used for 
osmotic purposes, it possessing the property of allowing the 
passage of fluids, such as solutions of salt, sugar, etc. 

VULCANIZED CELLULOSE (VULCANIZED FIBRE). 

Under this name a material is brought into the market 
by some English factories which, as regards its properties, 
is claimed to be very suitable as a non-conductor of heat 
and for insulating electric lines. According to Foster it 
consists essentially of a product which, as regards its mode 
of manufacture, closely resembles vegetable parchment, but 
it has the advantage that it can be made in pieces of any 
desired thickness, Avhich with vegetable parchment can only 
be done within very narrow limits. 

According to the description, vulcanized fibre is prepared 
by treating cellulose in a loose form, or in the form of paper, 
with a fluid consisting chiefly of sulphuric acid, to which, 
however, have been made such additions as will neutralize 
the progressive action of the acid when allowed to remain 
for a longer time in contact with the vegetable fibre. This 
is claimed to be attained by dissolving metallic zinc, and 
next dextrin, in the sulphuric acid. According to the patent 
specification, the process is as follows : For every 32 parts 
of ordinary sulphuric acid 1 part zinc is used, the mixture 



VEGETABLE PARCHMENT. 91 

being allowed to stand quietly till all the zinc is dissolved 
and the fluid has again acquired the ordinary temperature. 
In the fluid thus obtained, which represents a solution of 
zinc sulphate in an excess of sulphuric acid, dextrin is dis- 
solved, the proportion used being 1 part of dextrin to 4 parts 
of solution. 

While, as previously mentioned, the adhesive power of 
paper treated with sulphuric acid alone, disappears in a 
short time so that haste has to be made in combining two 
or more breadths of paper, paper treated in the above-men- 
tioned solution retains its adhesive and cementing powers 
for a much longer time, so that any number of breadths can 
be leisurely combined to one plate, or loose cellulose may 
bo shaped. The finished articles are first treated with solu- 
tion of common salt in water, and finally completely freed 
from adhering salts by long-continued washing with water. 
In the common-salt bath a transformation is claimed to 
take place, so that sodium sulphate and zinc chloride are 
formed which can be readily removed by washing. 

Very thick plates or otiicr thick articles may, it is 
claimed, be prepared from the mass by coating the parts to 
bs cemented together with the above-described solution, by 
which they are rendered adhesive and can be made into a 
single piece by pressing or rolling. 

Vulcanized fibre is found in commerce in two forms, 
namely, as a hard mass closely resembling wood in its 
properties, and as a soft, flexible and elastic substance be- 
having similarly to leather. The hard mass can be worked 
with the knife and saw, can be planed and turned, and, in 
a fresh state, can by pressure be molded into any desired 
shape ; two pieces may be glued together like wood. On 
account of being insendble to moisture and air, and by 
reason of its exceedingly slight power of conducting elec- 
tricity, the mass is claimed to be especially suitable for the 
manufacture of insulators for electrical purposes. The 
elastic mass is recommended for all purposes for which, at 



92 CELLULOSE, AND CELLULOSE PKODUCTS. 

the present time, leather or vulcanized rubber is generally 
used, for instance, for packing, valves, etc. 

In the description given above the statements made in 
the patent specifications have been accurately followed, and 
an attempt has been made to prepare vulcanized fibre in 
accordance with them, but entirely satisfactory results could 
not be obtained. While it cannot be denied that parch- 
mentizing in the fluid containing zinc and dextrin takes 
place more slowly than when working with sulphuric acid 
alone, it was impossible to obtain a mass approaching in 
solidity that of wood, or even of horn. The incompact 
masses could be quite completely freed from the acid and 
salts by repeated treatment with water, but this was very 
incompletely the case with the masses subjected to stronger 
pressure, so that in drying they fell to pieces by reason of 
sulphuric acid remaining behind. These observations jus- 
tify the conclusion that several things essential for the pre- 
paration of the vulcanized fibre mass have not been given 
in the patent specification, and that the product cannot be 
made by simply following the statements contained therein. 



V. 

PRODUCTION OF SUGAR AND ALCOHOL FROM 
WOOD-CELLULOSE. 

The fact that cellulose may be converted into ferment- 
able sugar by boiling it for some time with dilute mineral 
acid has been known for a long time. Although, theoreti- 
cally, the conversion of cellulose into sugar appears a very 
simple process, in practice on a large scale numerous diffi- 
culties are encountered. Although the first experiments in 
this direction were made as early as 1854, no process has 
been discovered up to the present time which could be used 
on a large scale with any prospect of success. Nevertheless, 
it would not seem that a mistake is made in saying that 
with the preparation of fermentable sugar from cellulose it 
will be exactly the same as with the production of pure 
cellulose from wood, several processes for that purpose 
being now known after many unsuccessful experiments had 
been made, and that a method for the production of fer- 
mentable sugar from wood-cellulose, which can be practi- 
cally applied, will also be finally found. 

In all the attempts to obtain fermentable sugar from cel- 
lulose, wood has heretofore been employed as the initial 
material, and that the results obtained with its use have 
comparatively given but little satisfaction, may possibly be 
chiefly due to the fact, that in the wood the individual vas- 
cular bundles, consisting of cellulose, are so firmly cemented 
together by the lignin as to make them in a high degree 
proof against the action of chemicals. 

Since a way for the destruction of the lignin and render- 
ing the cellulose accessible to the action of chemicals has 

(93) 



94 CELLULOSE, AND CELLULOSE PEODUCTS. 

been found in the progress made in this direction in the 
manufacture of cellulose, it seems reasonable to suppose 
that the time is drawing nearer when the question as re- 
gards the production of larger quantities of fermentable 
sugar from cellulose, relatively wood substance, will also bo 
solved. 

OLDER METHODS. - 

The first attempts to produce on a larger scale ferment- 
able sugar from wood were made b}' Zetterlund. He used 
fir sawdust and boiled it with 8 per cent, of its weight of 
h\'drochloric acid under a pressure of IJ pounds per square 
inch. After boiling for 8 hours, a fluid containing 3.38 
per cent, of dextrose was obtained, and after 11 hours, 
4.38 per cent. Calculated to sawdust, 19.G7 per cent, of 
the latter had been transformed. The fluid, after being 
separated from the solid residue, was neutralized with soda 
and then contained a quantity of common salt equal to the 
quantity of hydrochloric acid used. The fluid was brought 
into fermentation with yeast prepared from 22 pounds of 
malt extract and the fermented mass was subjected to dis- 
tillation. The yield of alcohol from 990 pounds of saw- 
dust amounted to 26.5 quarts. 

As will be seen from the figures given above, there is a 
considerable increase in the quantity of sugar obtained 
when boiling is continued for more than 8 hours. As the 
correct basis for an explanation of this increase, it may 
well be assumed that at the beginning of the action of the 
hydrochloric acid upon the wood, the tendency of the entire 
chenncal process was to attack the lignin by the acid and 
hence, as a preparatory operation, a gradual laying bare of 
the vascular bundles took place. Only after this process 
had progressed to a certain extent, the acid commenced to 
act upon the cellulose itself, a much more abundant forma- 
tion of sugar taking place than in the former period. 

There can scarcely be any doubt that with the use of a 
higher pressure and longer boiling, far larger quantities of 



SUGAR AND ALCOHOL FROM WOOD-CELLULOSE. 95 

sugar can be obtained from the wood than with Zetterlund's 
process. 

Since, for the purpose of obtaining celhilose, the disinte- 
gration of the wood may also be effected by acid, Bachet 
and Machard attempted to combine the production of sugar 
and cellulose in one process, so that the sugar solution 
might, in a certain measure, be obtained as a by-product in 
the manufacture of cellulose. (See p. 51). 

According to their process, the wood is boiled with dilute 
acid, the acid together with the sugar formed washed out 
with water and the remaining mass is comminuted in a 
hollander, bleached with chlorine gas and finally treated 
with soda lye. The product thus obtained cannot be called 
either mechanical pulp or cellulose, it being an intermedi- 
ary between both products but, as regards its properties, 
approaches more closely bleached mechanical pulp than 
ceHulose. On a large scale the operation is carried on as 
follows: The wood — fir or pine — is cut into thin discs. 
Four thousand four hundred pounds of these discs are 
brought into a vat together with 2,000 gallons of water and 
1,700 pounds of crude hydrochloric acid, and boiled for 12 
hours by direct steam, hence under ordinary pressure. 
The resulting fluid having been separated from the solid 
contents of the vat, is neutralized with upwards to 99 per 
cent, of calcium carbonate and fermented in the usual 
manner. I^y distilling the fermented fluid, a corresponding 
quantity of alcohol is produced, it being, however, not stated 
how large a quantity of it is obtained from the 4,400 
pounds of wood used. : . 

It is remarkable that according to Bachet and Machard's 
statements, neutralization of the acid should be effected by 
lime, since the fluid must then contain a corresponding 
quantit}^ of calcium chloride, and it is very questionable 
whether the fermentation of the sugar can proceed regu- 
larly in the presence of such a large quantity of a calcium 
salt. •■,.-'. . , . ■ . ,' 



96 CELLULOSE, AND CELLULOSE PRODUCTS. 

In addition to the processes above described, there are 
some other methods for the production of alcohol from 
wood, of which, however, but little is known, very likely 
for the reason that satisfactory results were noi obtained. 
One of these methods relates to the production of alcohol 
from beech. In this case, dilute sulphuric acid is made 
use of for the formation of sugar. Boiling is effected under 
a comparatively high pressure — 7 to 8 atmospheres — and 
continued for 10 to 12 hours. The final result was a com- 
paratively very small yield of raw alcohol of a disagreeable 
odor, while the solid mass which remained in the boiler 
showed a dark-brown color, had a disagreeable odor, and 
was not fit for anything but fuel. 

The failure of this experiment ma}'^ be explained from the 
process itself. At the high temperature which a fluid 
standing under a pressure of 7 to 8 atmospheres must 
acquire before it reaches the boiling point, the sugar already 
formed is again changed, and the production of a larger 
quantit}'^ of it entirely excluded. The poor quality of the 
raw alcohol obtained may be due to the properties of the 
wood used, beech containing a very large quantity of ex- 
tractive substances, which by the action of sulphuric acid 
very likely yield bodies of a disagreeable odor characteristic 
of the raw alcohol. That amongst these bodies are such as 
gradually acquire a dark color under the influence of the 
air, is shown by the fact that the raw alcohol in a very 
short time became dark brown. By repeated rectification, 
this disagreeable odor could only be diminished, its entire 
removal being impossible, and neither could the alcohol 
by rectification be brought to a state in which it remained 
colorless, becoming wine-yellow when for a short time ex- 
posed to the air. 

NATURE OF THE WOOD TO BE WORKED. 

The nature of the wood to be worked appears to exert 
great influence upon the yield of alcohol in general, as well 



SUGAR AND ALCOHOL FROM WOOD-CELLULOSE. 97 

as upon the quality of the product itself. Experiments 
made in this direction with pure cellulose gave much more 
satisfactory results than with wood itself, and the alcohol 
obtained could be quite readily purified by rectification. 
These facts serve as hints of how to proceed in order to ob- 
tain comparatively large yields of alcohol of sufllcient 
purity, as well as that great care has to be exercised in the 
selection of the wood to be used. 

Compact, heavy wood, containing large quantities of ex- 
tractive substances may at the outset be designated as un- 
suitable for the purpose. Such wood contains considerable 
quantities of lignin, tannin, coloring matter and other ex- 
tractive substances which cannot be converted into sugar, 
and hence beech, oak, chestnut, etc., are not available. 

The conifers — pine, fir, spruce, etc., — contain large quan- 
tities of rosin and volatile oils, the presence of which has a 
disturbing effect. Hence there is but little choice as re- 
gards the selection of wood for the production of alcohol, 
and only varieties with a white, incompact and soft wood 
can be used to advantage. Of the European varieties of 
wood, aspen, poplar, willow and linden, are the most suit- 
able materials for the purpose. 

A few remarks may here be made in reference to the ap- 
paratus to be used and the mode" of procedure in general. 
Since in starting a plant as, for instance, one required for 
working wood, machinery pla3's an important part, the entire 
execution of the plan is generally left to an engineer who 
puts up apparatus, boilers for boiling under pressure, etc., 
according to his own judgment without consulting the 
chemist as to the conditions the apparatus is to meet. The 
order in which the plant is to be managed is also, as a rule, 
indicated by the engineer who, in most cases, does not pos- 
sess the chemical knowledge, which is absolutely required 
if favorable results are to be obtained. 

Thus it may happen, as it actually did in the above- 
mentioned example, that wood is boiled under pressure 
7 



98 CELLULOSE, AND CELLULOSE PRODUCTS. 

with a comparatively very large quantity of sulphuric acid, 
the temperature becoming thereby so high that the newly- 
formed sugar was largely reconverted into other combina- 
tions and the yield in consequence was so small, that the 
entire expensive plant had to be abandoned and the ma- 
chinery sold for old metal. 

MORE MODERN METHODS. 

If the working of wood for the production of alcohol is to 
be carried on in a rational manner, i. e., in accordance with 
the laws of chemical science, it is absolutely necessary to 
proceed according to the following principles : 

The soft, white wood cut into thin discs should for a con- 
siderable time be submerged in running water, the object of 
this soaking being to free the wood as much as possible 
from water-soluble extractive matter such as albumen, 
tannin and other substances, so that only the vascular 
bundles cemented together by the lignin remain behind. 

The wood when sufficiently soaked is to be cut into small 
pieces as if it were to be worked for cellulose by the soda or 
sulphite process. This reduction is necessary, on the one 
hand, to give the w^ood a very large surface, thus present- 
ing to the acid manj' points of attack, and on the other, 
because the residue which remains behind after treating 
the wood with acid, can thus be best utilized for the prepar- 
ation of cellulose. 

Hydrochloric acid is most suitable for converting the 
cellulose into sugar, it being preferable to sulphuric acid, 
if only for the reason that even at a high temperature it 
does not form brown, coal-like combinations froiii the cell- 
ulose. 

Since by boiling under increased pressure a much larger 
quantity of sugar can be obtained than by boiling under 
ordinary conditions, an increased pressure will have to be 
worked with, and the use of a closed boiler would, therefore, 
seem to be one of the conditions for attaining favorable re- 
sults. 



SUGAR AND ALCOHOL FROM WOOD-CELLULOSE. 99 

For boiling, a vertical, iron vessel furnished with a re- 
movable lid, steam heating and safety-valve will have to 
be used. Since iron is vigorousl}' attacked by the vapors 
of hydrochloric acid, the boiler will have to be lead-lined, 
this metal being least attacked by the vapors. In order to 
save the lead-lining, a wooden vessel which almost fills the 
boiler, may be placed in the latter. This wooden vessel 
serves for the reception of the comminuted wood and the 
fluid, and when boiling is finished and its fluid contents 
have been discharged, it is lifted from the boiler by means 
of a hoist. 

When the boiler has been charged with the coraminnted 
wood and dilute hydrochloric acid, the apparatus is closed 
air-tight and the fluid is brought to boiling by means of 
steam of such a tension that the contents of the boiler are 
not heated to above 230° or 233.6° F., boiling being con- 
tinued for a suitable time, and very likely 10 to 12 hours 
will be required until a sufliciently large quantity of sugar 
will have formed. There being no data on hand regard- 
ing the time required for obtaining the largest possible 
quantity of sugar, and this time varying probably for 
every variety of wood and for difl'erent concentrations of 
the acid, it must be determined by experiments. Such ex- 
periments or tests are made by taking every hour samples 
from the boiler and determining the content of sugar. If, 
in the disintegration of wood, the conditions should be 
similar to those in the disintegration of starch for the pur- 
pose of producing grapotsugar, it will be observed by the 
samples that the quantity of sugar formed within a certain 
time increases quite regularly until a period is reached 
when the further formation of sugar becomes very sluggish, 
so that for reasons of expediency the operation may be con- 
sidered finished. 

Since the hydrochloric acid does not undergo a change in 
converting a portion of the cellulose into sugar, but acts by 
its mere presence, the fluid at the end of the operation will 



LtfCi 



100 CELLULOSE, AND CELLULOSE PRODUCTS. 

contain as much free hydrochloric acid as was originally 
present, and this acid has to be removed as far as possible. 
This may be effected, when the formation of sugar is com- 
plete, by connecting the lid of the boiler with a lead cool- 
ing coil in a cooling vat, and distilling off a portion of the 
fluid, boiling being continued under the ordinary pressure. 
The greater portion of the hydrochloric acid present in the 
fluid will thereby escape together with the steam, and will 
be again condensed in the cooling coil. The dilute hydro- 
chloric acid thus obtained may be used for the next 
operation. Distillation may be continued until the fluid 
contains only 3 per cent, of free acid, when the operation 
is interrupted. 

When this point has been reached, the fluid is dis- 
charged from the boiler, the boiling vessel hoisted from the 
latter, and replaced by another which has in the meantime 
been charged with wood, so that with the exception of the 
short time required for emptying and recharging the boiler, 
the operation can be carried on without interruption. 

The unchanged wood remaining in the boiler is still 
saturated with the acid, sacchariferous fluid. This fluid 
is obtained by repeatedly washing the wood with water, 
but it cannot be recommended to combine it with the 
fluid first obtained, otherwise the sugar solution would be 
too much diluted. The fluid used for washing the wood 
is utilized in the next operation in place of pure water, 
the hydrochloric acid as well as the sugar contained in it 
being thus completely exhausted. 

The sugar solution discharged from the boiler is now 
neutralized with soda to such an extent that its content of 
free hydrochloric acid is reduced to 1 per cent., the compo- 
sition of the fluid being then such that yeast can live in it, 
provided it is furnished with the requisite quantity of nour- 
ishing salts. 

This object may be attained by adding to the fluid cooled 
to about 86° F., 5 per cent, of yeast prepared from crushed 



SUGAR AND ALCOHOL FROM WOOD-CELLULOSE. 101 

malt. It is, however, also possible to make use of a cheaper 
method by adding directly to the fluid salts serving as nu- 
triment of the 3^east, equal parts of potassium phosphate and 
^ ammonium phosphate being very suitable for the purpose. 
One part of the nourishing salt for 1000 parts by weight of 
the fluid is used. These salts dissolving with ease in water, 
a solution of them is prepared in a small quantity of the 
fluid and uniformly distributed throughout the sugar solu- 
tion by stirring. 

Fermentation can be induced either by freshly-compressed 
yeast or by freshly-prepared distillery yeast. With the 
fluid at a temperature of 86° F., propagation of the yeast 
takes place very rapidly, and in a short time the fluid is in 
a state of vigorous fermentation. Regarding the quantity 
of compressed yeast to be used it may be said that \ part 
by weight of it suffices for 100 parts by weight of the sugar 
contained in the fluid. 

The fluid is now left to itself until fermentation is fin- 
ished, which with the high temperature at which it was in- 
duced, will be the case in, at the utmost, 36 hours. It is 
then drawn off from the yeast at the bottom of the vat, and 
immediately subjected to distillation. The yeast need not 
be removed from the vat but can be utilized in the next 
operation. 

Distillation of the fermented fluid should be effected in 
an apparatus which allows of the alcohol being rectified as 
far as possible, i. e., to somewhat above 96 per cent. Wood 
alcohol always has a peculiar odor due to small quantities 
of combinations, the chemical nature of which is not de- 
finitely known. Ho^rever, by careful rectification these 
bodies can be so completely separated from the alcohol that 
it possesses only the odor of the pure product. 

When soft, white varieties of wood are in the above 
described manner treated with hydrochloric acid, the resi- 
due remaining behind retains its color unchanged, provided 
the acid used is free from iron. However, ordinary crude 



102 CELLULOSE, AND CELLULOSE PRODUCTS. 

hydrochloric acid, which will have to be used when working 
on a large scale, alwaj'S contains a certain quantity of iron, 
and the wood shows generally a slightly brownish color, so 
that when further worked to cellulose it does not yield an 
entirely pure white product, which can, however, be so 
made by bleaching. 

Supposing that 20 per cent, of the weight of the wood 
can be converted into fermentable sugar, and assuming that 
this quantity of sugar after fermentation and deduction of 
unavoidable losses yields in round numbers 10 liters of 
alcohol : by taking the value of 1 liter of alcohol at only 
10 Pfennige * it will be seen that the alcohol obtained from 
100 kilogrammes (220 lbs.) has a value of 1 mark,t and 
that the remaining 80 kilogrammes (193.6 lbs.) of wood arc 
available for further working into cellulose. Hence the 
calculated results, even with such small yields and low 
price of the alcohol produced as have been assumed above, 
are by no means unfavorable, and it might certainly prove 
a profitable undertaking for a chemist to investigate closely 
the subject, working especially with a view towards increas- 
ing the yield of sugar from the wood. 

Classen's process. 

The chemist Classen has recently devoted much time to 
the solution of the problem of producing directly-ferment- 
able sugar from wood, having adopted entirely new methods, 
which, according to his statements, have actually resulted 
in comparatively large yields. 

According to a process patented by him the wood is first 
treated with sulphuric acid, having a concentration of the 
so-called chamber acid — 50° to G0° Be. — and then sub- 
mitted to powerful mechanical pressure, the effect of the 
latter, it is claimed, being to convert a large portion of the 

*1 Pfennig = 0.23G cent. 
1 1 Mark = 23. G cents. 



SUGAR AND ALCOHOL FROM WOOD-CELLULOSE. 103 

cellulose contained in the wood into dextrose. (?) The mass 
need then only be diluted with water and boiled for some 
time at the ordinary pressure to accomplish complete (?) 
conversion into dextrose. 

Air-dry sawdust, which in this state contains in round 
numbers 15 per cent, of water, is used as raw material. A 
portion of the sawdust is intimately mixed with three- 
fourths its quantity of sulphuric acid of 57° Be., a mass of 
a peculiar greenish color being thereby formed. By ex- 
tracting this mass with water a fluid is obtained in which 
no sugar can be found. By subjecting it, however, to 
strong pressure by means of a powerful hydraulic press a 
vigorous chemical reaction takes place, the mass becoming 
highly heated and its color being changed to nearly black, 
so that it presents the appearance of wood which has been 
carbonized by highly concentrated sul2:)huric acid. On ex- 
tracting the pressed mass with water the latter shows a very 
distinctive sugar-reaction. 

According to close investigations, it is claimed that in 
consequence of the pressure, the greater portion (?) of the 
wood-fibre is converted into cellulose, and in addition there 
are present other bodies which, as regards their properties, 
occupy intermediate positions between dextrin and dextrose. 
For the conversion of all (?) the dissolved bodies into dex- 
trin, it suffices to mix the pressed mass with water in the 
proportion of 1 part of the substance originally used to 4 
parts of water, and to boil it for half an hour in an open 
vessel. By this process a fluid is said to be obtained which 
is free from the intermediate products interfering with fer- 
mentation otherwise found in dextrose solutions prepared 
from wood. 

If the process above described is actually available in 
practice, it may be supposed that the first eff'ect produced 
by the sulphuric acid upon the wood is to destroy the en- 
crusting substance — the lignin — so that the pure cellulose 
becomes accessible to the further action of the acid. It re- 



104 CELLULOSE, AND CELLULOSE PRODUCTS. 

mains still to be established by experiments, whether the 
conversion of this cellulose into dextrose cannot be attained 
by simply heating the green mass to a certain temperature 
without the use of strong pressure. 

A decided disadvantage of this process is, however, the 
use of a quantity of sulphuric acid which is exceedingly 
large in comparison with the quantity of wood to be 
worked, amounting in round numbers to 75 per cent, of the 
latter; and to bring the dextrose solution finally obtained 
into fermentation, this quantity of sulphuric acid must be 
nearly neutralized by the addition of lime. Hence, it will 
be necessary to recover the considerable quantity of dex- 
trose solution adhering to tlie resulting gypsum by system- 
atic washing of the latter. The quantities of gypsum 
which would finally accumulate in carrying on the opera- 
tion on a more extensive scale, would be very large and 
difficult to utilize, so that the cost of producing ferment- 
able sugar according to this process would be comparatively 
quite high. 

It would appear that the inventor of the above-described 
process was himself not entirely satisfied with the results, 
and continued his investigations in regard to the produc- 
tion of dextrose from wood in another direction. A note- 
worthy process, also patented by Classen, is based upon the 
principle that by the action of watery sulphurous acid at a 
higher temperature, wood-substance is disintegrated to such 
an extent that the presence of a very small quantity of 
sulphuric acid suffices for the conversion of a very consid- 
erable quantity of cellulose into fermentable sugar. 

In the commencement of the operation a fluid consisting 
of a concentrated solution of sulphurous acid containing 
0.2 per cent, of sulphuric acid is used, or sulphurous acid 
alone is employed, the latter, at a certain stage of the pro- 
cess, being partially converted into sulphuric acid so that 
at the moment of its nascency it acts upon the cellulose. 

The maximum yield of dextrose is obtained by conduct- 



SUGAR AND ALCOHOL FROM WOOD-CELLULOSE. 105 

ing the operation so that the formation of sulphuric acid 
takes place at a period when the temperature in the boiler 
is between 248° and 293° F. In this case, it is claimed, 
that from every kilogramme (2.2 lbs.) of Avood (dry sub- 
stance) at least 300 grammes (10.58 ozs.) of dextrose are 
obtained, of which, on an average, 80 per cent, is ferment- 
able. Hence, in round numbers 120 grammes (4.23 ozs.) 
of absolute alcohol would be obtained from 1 kilogramme 
(2.2 lbs.) of anhydrous wood-substance. 

The temperature required for the formation of dextrose 
after the wood has been previously disintegrated by the 
action of sulphurous acid, depends on the nature of the wood 
to be worked, a temperature of 267° F. sufficing for birch, 
while for fir one of upwards to 293° F. is necessary. While 
a certain quantity of dextrose is without doubt formed 
below these temperatures, it is a comparatively very small 
one. 

The production of sulphuric acid at a certain stage of the 
process may be effected in various ways, the simplest 
method being to introduce into the vessel atmospheric air 
or a gas mixture rich in oxygen, or by adding manganese 
suboxide or peroxide, which yield a portion of their oxygen, 
a corresponding quantity of sulphurous acid being thereby 
converted into sulphuric acid. 

From what has been said above, the main point of the 
process consists m treating the wood in an autoclave with 
the sulphurous acid solution until the temperature reaches 
248° to 293° F., then bringing about the formation of sul- 
phuric acid and continuing heating for 10 to 15 minutes 
longer. 

Although Classen appears to lay great stress upon the 
fact that the sulphuric acid acts at the moment of its forma- 
tion upon the cellulose, he remarks directly in connection 
with the description of his process given above, that in place 
of sulphuric acid, a mixture of sulphurous acid with some 
other inorganic acid, for instance, hydrochloric acid of a 



lOG CELLULOSE, AND CELLULOSE PRODUCTS. 

concentration of 0.2 per cent, or more, may also be used. 
If such is actually the case, the particular action which the 
sulphuric acid is claimed to exert at the moment of its forma- 
tion, is virtually eliminated, and the use of sulphurous acid 
for the disintegration of the wood remains as the only main 
feature of the entire process. It must be admitted that the 
figures given above regarding the yield of fermentable 
sugar are excellent, and for this reason alone the process 
deserves serious consideration. 

Experiments made by Classen to effect the disintegration 
of the wood by means of chlorine or hypochlorides yielded 
favorable results also. The wood, together with a half per 
cent, chlorine water, is heated to between 248° to 293° F., 
and sulphurous acid is then introduced into the vessel and 
rapidly converted into sulphuric acid by the action of the 
chlorine. 

Another process, also patented by Classen, consists in the 
action of sulphuric acid, just formed from sulphuric anhy- 
dride, upon the wood. Vapors of sulphuric anhydride 
mixed with vapors of sulphur dioxide are conducted upon 
the moist sawdust. I'he sulphur dioxide on coming in 
contact with the water contained in the sawdust is con- 
verted into sulphurous acid, and the wood is by the latter 
disintegrated in the manner already explained. The sul- 
phuric anhydride on coming in contact with the water is 
transformed to sulphuric acid, which at the moment of its 
formation is said to possess great inverting power. Classen 
claims to effect the treatment of the wood with sulphuric 
anhydride in revolving lead-lined drums, and accelerates 
the operation by previously heating the drums to from 86° 
to 104° F. The resulting mass is then pressed until it is 
hard and of a dark color, when it is treated with four times 
its quantity of water, and after neutralization of the acid is 
subjected to fermentation. Classen has found it suitable to 
heat the mass treated with sulj)huric anhydride for some 
time in a closed vessel to between 257° and 275° F., the 
formation of sugar being thereby still further increased. 



SUGAR AND ALCOHOL PROM WOOD-CELLULOSE. 107 

Sulphurous acid possessing in an uncommon degree the 
property of checking fermentation, it would appear abso- 
lutely necessary to free the fluid containing dextrose com- 
pletely from it before submitting it to fermentation, and 
this can only be with certainty effected by boiling continued 
for a longer time. Only when a test of the fluid as to the 
presence of sulphurous acid yields a negative result, the free 
acid still present can be almost completel}' neutralized, and 
the fluid set for fermentation. The presence of a smaller 
quantity of acid does not impede fermentation, but is rather 
beneficial, since yeast thrives very well in an acid fluid, 
while certain other organisms, which bring about by- 
fermentations, cannot develop it. 

A further modification of Classen's process consists in the 
wood being simultaneously exposed to the action of two 
acids at the moment of their liberation. The wood is first 
heated, together with sulphurous acid, to between 266° and 
293° F., then allowed to cool to 248° or 266° F., when 
chlorine water is introduced into the fluid. In this case, 
sulphuric acid, as well as hydrochloric acid, is formed, and 
the presence of both of these acids is said to have a favora- 
ble effect upon the conversion of cellulose into dextrin. 
The quantity of chlorine to be used must be sufficiently 
large, so that at least 0.2 per cent, of sulphuric acid is formed. 

If, as previously stated, 120 grammes (4.23 ozs.) of pure 
alcohol can be obtained from 1 kilogramme (2.2 lbs.) of 
perfectly dry wood-substance by one of Classen's processes, 
it would be well adapted for working on a large scale. 
Regarding the residue of substance not converted into dex- 
trose, it could very likely not be utilized for any other 
purpose than for burning under the boilers of the plant. 



VI. 

PREPARATION OF OXALIC ACID FROM WOOD 
CELLULOSE. 

When an organic substance is heated, together with 
caustic alkalies, to a certain quite high temperature, it is 
completely decomposed, and among the products of decom- 
position is alvvaj's found a certain quantity of oxalic acid. 
The organic substances behave thereby, however, in such a 
manner that from bodies of animal origin but small quan- 
tities of oxalic acid can be obtained, while substances 
derived from the vegetable kingdom yield such a large 
quantity of it that it may almost be designated as the 
chief product of the processes of decomposition. A series 
of exact experiments with various substances of vegetable 
origin have led to the result, that the yield of oxalic acid is 
the greater the more closely the vegetable substances used 
approach the pure carbohydrates in their composition. 

In accordance with this, starch, pure cellulose, etc., give 
comparatively the largest yields of oxalic acid. Since, in 
addition to cellulose and lignin, wood contains but small 
quantities of other bodies, it is especially suitable for the 
preparation of oxalic acid, and the more so as sawdust, 
which otherwise is of but little value, is the best material 
for the purpose. Though there is considerable difference 
in the various kinds of wood as regards the extractive sub- 
stances contained in them, oak being, for instance, very 
rich, and poplar very poor in them, this fact exerts but 
little influence upon the yield of oxalic acid, Avhich justifies 
the conclusion that the extractive substances — tannin, col- 
oring matter, etc. — as well as the wood-substance itself, may 

(108) 



OXALIC ACID FROM WOOD-CELLULOSE. 109 

l^e converted into oxalic acid. Since all substances con- 
taining cellulose form an equally good material for the 
production of oxalic acid, all waste products of this kind 
may be used, and in addition to sawdust, waste from the 
manufacture of wood-cellulose and vegetable parchment, as 
well as scraps of tissue of vegetable origin may be utilized. 
The formation of oxalic acid from the above-mentioned 
substances talces place by heating them together with a 
certain quantity of caustic alkali — potassium or sodium 
hydroxide, or a mixture of both — to above 392° F. It 
may, however, be mentioned as a remarkable fact that 
sodium hydroxide, when used by itself, gives but a very 
small yield of oxalic acid, while caustic potash forms con- 
siderably larger quantities, and the best results are obtained 
when both the alkalies, mixed in a certain proportion, are 
allowed to act upon the saw-dust. There is no theoretical 
explanation of these facts, which have been established by 
experiments made with the greatest exactness. 

thorn's investigations. 

According to investigations made in this direction by 
Thorn, 50 parts of sawdust heated with 100 parts of caustic 
soda to a temperature of 392° F. yield a quantity of crys- 
tallized oxalic acid equal to 30 per cent. By doubling the 
quantity of caustic soda a greater yield is obtained. Thus 
25 parts of sawdust heated with 100 parts of caustic soda 
yielded, when melted in a dish at a temperature of 464° F., 
a quantity of oxalic acid which, calculated to 100 parts of 
sawdust, amounted to 42.30 per cent. However, an ex- 
periment made with the same quantities of both substances 
spread out in a thin layer and heated to 464° F. resulted in 
a yield of 52.14 per cent. 

Further investigations by Thorn refer to the quantities 
of oxalic acid which can be obtained by the action of a 
mixture of caustic soda and caustic potash upon sawdust. 
Thorn extended these investigations still further by examin- 



110 'CELLULOSE, AND CELLULOSE PRODUCTS. 

ing into the behavior of the various mixtures when they 
were melted together with sawdust in dishes, or when the 
masses were heated in thin layers. The figures indicating 
the yield of oxalic acid under these different conditions give 
at the same time a hint of how the manufacture has to be 
ciirried on in order to obtain the greatest possible yield. 

1. Yields of oxalic acid by heating sawdust with a mix- 
ture of caustic soda and caustic potash in thin layers — 2 
parts of alkali hydroxide to 1 part of sawdust were used. 



Proportion 


between caustic 


Temperature, 


Yield of oxalic acid from 


potash and caustic soda. 


°F. 


100 parts of wood. 


20 


80 


374 


19.78 


20 


80 


892 


21.50 


20 


80 


464 


30.04 


30 


70 


374 


21.38 


30 


70 


464 


38.39 


40 


60 


374 


14.00 


40 


60 


£92 


30.35 


40 


60 


464 to 473 


43.70 


50 


50 


392 


25.76 


50 


50 


464 to 473 


89.04 


60 


50 


392 


cO.57 


CO 


40 


464 to 473 


42.67 


80 


20 


392 to 428 


45.59 


80 


20 


464 


61.32 


90 


10 


464 


64.24 


100 


— 


464 to 473 


65.57 



By treating the sawdust with one of the mixtures of 
caustic alkalies given above, its color is changed as soon as 
the temperature exceeds 284° to 302° F., becoming at 
first brownish, which soon yields to a greenish-yellow tone. 
The mass then acquires a pasty condition, and at 356° F. 
evolves heavy nebulous vapors. That at tliis temperature 
reaction commences to be most energetic is evident from 
the fact that the action continues even if further heating 
is entirely interrupted. The temperature of the mass then 
gradually rises to above 680° F., the mass swells up, 
evolves a large quantity of combustible gases and finally 



OXALIC ACID FROM WOOD-CELLULOSE. Ill 

carbonizes completely when a mixture of 90 parts of caustic 
soda, 10 parts of caustic potash and 50 parts of wood has 
originally been used. This proves that with the use of a 
mixture containing such a small quantity of caustic potash 
the production of somewhat larger quantities of oxalic acid 
would be impossible as the temperature of the mass could 
not be regulated. 

In the same degree as the quantity of caustic potash in 
the mixture is increased and that of caustic soda is de- 
creased, the reaction takes place less violeiltly, and it is 
possible to maintain the temperature of the mass within the 
limit of 464° F. 

According to the series of figures given above the best 
proportion between caustic potash and caustic soda would 
be to use 80 parts of caustic potash to 20 parts of caustic 
soda, or 90 parts of the former to 10 of the latter. The 
temperature has to be raised to above 464° F. in order to 
obtain a yield of over 60 per cent, of oxalic acid. 

As will be seen from the above-mentioned figures, a con- 
siderably larger yield of oxalic acid is obtained, if the mix- 
ture be heated in a thin layer, the great advantage of this 
mode of procedure, when working on a large scale, consist- 
ing in the fact that the temperature of a mass can be more 
readily kept within the prescribed limits than when work- 
ing in deep vessels. For this purpose. Thorn has deter- 
mined the following proportions : 

Proportion between caustic 
potash and caustic soda. 






100 


10 


90 


20 


80 


30 


70 


40 


CO 


60 


40 


80 


20 



100 



Temperature, 


Yield of oxalic acid from 


°F. 


100 


parts of wood. 


392 to 408 




33.14 


446 




58.36 


464 to 494 




74.76 


464 to 494 




76.77 


464 to 494 




80.57 


464 to 494 




80.08 


473 




81.24 


464 to 494 




81.23 



Solutions of quite high concentration (40° B6.) of the 



112 CELLULOSE, AND CELLULOSE PEODUCTS. 

caustic alkalies containing potash and soda in appropriate 
proportions are first prepared, and heated to the boiling 
point. The sawdust is then introduced, the proportions 
being so chosen that for 2 parts of alkali hydroxide one 
part of wood is used. In introducing the sawdust care 
should be taken to see that it is uniformly distributed 
throughout the .fluid and, if the latter had a concentration 
of 40° Be., it will be completely absorbed by the sawdust. 

The mixture is then evenly spread out upon iron pans 
in layers not exceeding 0.39 inch in thickness and heated 
as uniformly as possible, the premature melting of the mass 
being as far as possible prevented by frequent stirring. 
However, as the temperature soon rises above 392° F., par- 
tial fusion can no longer be prevented, and the mass becomes 
moist and crummy. Heating is continued for 1 to 1|^ hours, 
the temperature being only gradually allowed to rise to 
494° F. 

As shown by the table given above, a mixture of 40 
parts of caustic potash and 60 parts of caustic soda gives 
exactly the same jneld of oxalic acid as pure caustic potash 
by itself, but the price of the latter being much higher than 
that of caustic soda, it will be of advantage to use in prac- 
tice the two alkalies in the proportion given above. 

The turbulent reaction during fusion may, it is claimed, 
be prevented, so that the preparation of oxalic acid takes 
place quietly and smoothly', by adding to the mixture of 
sawdust and alkalies heavy hydrocarbons, for instance, 
machine oil or vaseline oil, and, according to Capitaines 
and Hertlings, who have patented a process for this pur- 
pose, the use of caustic soda by itself suffices for the forma- 
tion of abundant quantities of oxalic acid. They use a 
soda lye of 1.35 specific gravity in the proportions of 40 
parts of sodium hydroxide to 20 parts of sawdust and 1.5 
parts of hydrocarbon combinations. The temperature need 
not exceed 392° F., and the resulting yield of oxalic acid is 
•claimed to amount to 140 parts for every 100 parts of wood. 



OXALIC ACID FROM WOOD-CELLULOSE. 113 

PREPARATION OF OXALIC ACID ON A LARGE SCALE. 

With the use of the process introduced by Thorn, the 
preparation of oxalic acid is divided into the following 
operations : 

Preparation of the mixed caustic lyes and their concen- 
tration by evaporation to a specific gravity of 1.35. 

Mixing the lye with the sawdust and heating the mix- 
ture to the maximum temperature to be used. 

Production of sodium oxalate from the melt, conversion 
of it into calcium oxalate, and separation of the oxalic acid 
from the latter ; recrystallization of the crude oxalic acid. 

In preparing the mixed lyes the content of pure potas- 
sium carbonate and sodium carbonate in the potash and 
soda to be used has first to be determined, and the two salts 
must be mixed in such a proportion that the lye contains 
exactly 40 parts of caustic potash and caustic soda. The 
solution of the salts is made caustic in the usual man- 
ner by means of quicklime, and evaporated in iron pans 
to 1.35 specific gravity. It is then immediately mixed with 
the sawdust in the proportion of 1 part of the latter to 2 
parts of alkali. 

MELTING APPARATUS. 

The apparatus for heating the mass to the maximum 
temperature required for the formation of oxalic acid must 
be of such a nature that the temperature of the mass can be 
readily regulated, and that the workmen are completely 
protected from the vapors evolved from the mass during 
heating. These vapors have a troublesome effect upon the 
respirator}' organs and eyes, and provision for their imme- 
diate removal has therefore to be made. This may be 
effected by placing over the plates upon which heating 
takes place, a jacket extending down as far as possible with- 
out impeding the work. The jacket terminates above in a 
shaft in which a very strong current of air is produced by a 
steam ejector or a fan. In this manner the vapors arising 



114 CELLULOSE, AND CELLULOSE PRODUCTS. 

from the plates are imraediately carried away and blown 
into a high chimney or, still better, under the grate of a 
fireplace. 

Since in heating the mass the temperature must not ex- 
ceed 494° F., it would seem advisable to effect heating the 
plates b}'^ means of a current of hot air or superheated steam, 
the use of an iron box 4 to 6 inches deep and 6J feet long 
and wide being most suitable for the purpose. On the front 
of the box, i. e., the side turned towards the workmen, is a 
pipe through which the heated air or superheated steam 
passes into the box, the pipe being furnished with a stop- 
cock, by means of which heating can be regulated as desired. 

To prevent the mass spread out upon the surface of the 
box from acquiring in some places too high a temperature, 
it has to be frequently turned, and it is advisable not to use 
for this purpose iron hand-rakes, but to employ a mechan- 
ical contrivance similar to that used in malt-houses for 
turning the malt in the kiln. Such a contrivance can be 
run by a small motor so that the entire attention of the 
workmen is directed towards the mass in hand. 

The mass having been spread out upon the iron plate in 
a somewhat thicker layer than is possible without the use 
of a mechanical turning contrivance, a full current of steam 
or hot air is immediately admitted for the purpose of 
rapidly heating it and evaporating the water still adhering 
to it. To prevent caking, the turning apparatus is at once 
set to work. 

The temperature maj' now in a short time be brought to 
392° or 410° F., and then gradually raised to 464° or 473° 
F. At this temperature the mass is kept for from one to one 
and a half hours, the admission of steam or hot air being so 
regulated that the temperature cannot rise any higher. 
The mass is now considered finished and removed from the 
heating apparatus by means of iron rakes. 



OXALIC ACID FROM WOOD-CELLULOSE. 115 

WORKING UP THE MELT, 

The mass contains all the sodium held by it fixed to 
oxalic acid ; in addition it contains potassium carbonate 
and humus substances which give it a quite dark colora- 
tion. The mass is immediately thrown into a vessel con- 
taining a certain quantity of water, which is in a short time 
brought to boiling, and in this state rapidly dissolves the 
sodium oxalate. It is advisable to place in the vessel a 
steam coil to be able to directly heat the fluid. Only 
enough water is used for the boiling fluid to show a density 
of 35° Be. The boiling fluid is allowed to run through a 
filter of close linen into a vessel in which, under constant 
stirring, it is rapidly cooled to the ordinary temperature. 

Sodium oxalate dissolves with ease only in boiling water, 
it being but slightly soluble in cold water and, hence, by 
rapid cooling, a pasty mass consisting of very small crystals 
of quite pure sodium oxalate is obtained. This pasty mass 
is treated in a centrifugal for the removal of the mother-lye 
adhering to the crystals. 

In addition to a very small quantity of sodium oxalate, 
the mother-lye contains the total quantity of the potash 
used in the form of potassium carbonate, and the humus 
substances which have been formed by heating the mass. 
The mother-lye is utilized by converting the potassium car- 
bonate into caustic potash by means of quick-lime, and 
using it for the next operation. 

However, in the course of several operations, the humus 
substances accumulate to such an extent in the mother-lye 
as to render it inadvisable to make it again caustic. It is 
then utilized for obtaining jiure potassium carbonate, this 
being eff^ected by mixing it with a sufficient quantity of 
sawdust to make a mass which can be taken up with 
shovels. This mass is burnt in a small reverberatory fur- 
nace, and the residue of ash calcined until white. It then 
consists of almost pure potash which may be used for further 
operations. 



116 CELLULOSE, AND CELLULOSE PRODUCTS. 

For the purpose of obtaining pure oxalic acid from the 
crude sodium oxalate, the oxalic acid is first fixed to lime, 
and the resulting calcium oxalate, which dissolves with dif- 
ficulty, is decomposed by sulphuric acid, a solution of the 
oxalic acid being thereby obtained. 

This operation is carried on by dissolving the crude 
sodium oxalate in boiling water in a vat furnished with a 
stirrer which is kept in constant motion. Milk of lime is 
then added to the boiling solution, whereby calcium oxalate, 
which dissolves with difficulty, and free caustic soda are 
formed. During the precipitation of the calcium oxalate, 
the fluid has to be constantly kept near the boiling point, as 
only under this condition, the precipitate turns out granular 
and settles rapidly on the bottom. 

A sample is from time to time taken from the vat, fil- 
tered, acidified first with an excess of acetic acid, and then 
solution of calcium chloride is added. If the sample still 
gives a precipitate it is an indication that the total quantity 
of the sodium oxalate has not been decomposed and more 
milk of lime has to be carefully added. When the sample 
shows that decomposition is complete, the stirrer is stopped, 
the precipitate allowed to settle, and the supernatant caustic 
lye is drawn off. The precipitate is then several times 
washed with water, and the wash-waters are combined with 
caustic lye first drawn off". The total quantity of fluid thus 
obtained is evaporated in iron pans until the soda lye shows 
a specific gravity of 1.35, and can then be utilized for work- 
ing fresh quantities of sawdust. 

The calcium oxalate having been sufficiently washed is 
brought into a lead-lined vessel upon the bottom of which 
rests a steam coil, and mixed with a sufficient quantity of 
water to form a thin paste. While steam is being intro- 
duced through the narrow apertures with which the steam 
coil is furnished, dilute sulphuric acid (of 15° to 20° Be) is 
allowed to run in. The quantity of sulphuric acid required 
can be approximately calculated, but in order to separate 



OXALIC ACID FROM WOOD-CELLULOSE. 117 

all the oxalic acid and, at the same time, have no excess of 
sulphuric acid in the fluid, a sample of the latter has from 
time to time be tested. This is effected by bringing a small 
quantity of the white precipitate separated, which is to con- 
sist of gypsum, upon a filter, washing quickly with water, 
and then treating the mass with a small quantity of sul- 
phuric acid. The filtrate now obtained is mixed with solu- 
tion of potassium permanganate. If undecomposed calcium 
oxalate is still present in the vat, the fluid, which imme- 
diately after the addition of the potassium permanganate 
appears red, becomes discolored by the decomposition of the 
latter. If the fluid remains red, decomposition of the cal- 
cium oxalate is complete. 

PRODUCTION OP PURE OXALIC ACID. 

The vat now contains a solution of oxalic acid in water 
standing over the precipitate consisting of calcium sulphate. 
The solution is drawn ofi^, the precipitate is several times 
washed with water to obtain the last traces of oxalic acid, 
and the oxalic acid solution is finally highly concentrated 
by evaporation, the latter being effected in pans very 
similar to those used for evaporating solutions in the manu- 
facture of tartaric acid. The pans consist of large, shallow, 
lead-lined wooden boxes, furnished with a lead heating 
coil. Two such evaporating pans are placed one above the 
other so that the contents of the one placed at a higher 
level can be discharged into the lower pan. 

The oxalic acid solution is first brought into the upper 
pan and evaporated to a density of 15° Be. It is then 
allowed to cool and run into the lower pan. The reason 
for this interruption of the evaporation is that the dilute 
solution of oxalic acid contains quite a large quantity of 
gypsum in solution, and the latter separates completely 
only when the fluid has acquired the above-mentioned con- 
centration. After removing the precipitated gypsum from 
the bottom of the pan, the latter is again charged with 



118 CELLULOSE, AND CELLULOSE PRODUCTS. 

crude oxalic acid solution. The solution in the lower pan 
is evaporated to 30° B6., and then left to crystallize either 
in large stoneware dishes or in lead-lined vats. It is ad- 
visable repeatedly to stir the fluid during cooling, small 
crystals which include but little mother-lye being thereby 
obtained. 

When the fluid in the cr^'^stallizing vessels has become 
entirely cold, the crystals are freed as far as possible from 
raother-lye by treatment in a lead-lined centrifugal, the 
crystals of crude oxalic acid thus obtained being available 
for many technical purposes as their slightly brownish 
color is not objectionable. 

An almost chemically pure product is produced from the 
crude oxalic acid by dissolving the latter in the smallest 
possible quantity of boiling water, and stirring into the hot 
solution a small quantity of finely-powdered animal cliar- 
coal. The fluid is then allowed to stand until the animal 
charcoal powder has settled on the bottom of the vessel, 
and the at first brownish fluid has become as clear 
as water. The hot solution is then allowed to run in a thin 
stream into the crystallizing vessel and the resulting crys- 
tals are completely dried by whirling in a centrifugal. 
The oxalic acid thus purified contains neither free sulphuric 
acid nor calcium oxalate, and may be considered a highly 
refined article. 

The mother-lye obtained by the first treatment of the 
crystals of crude oxalic acid in the centrifugal contains 
considerable quantities of free sulphuric acid, and the latter 
is made use of by employing the mother-lye in the next 
operation of decomposing the calcium oxalate, a smaller 
quantity of sulphuric acid being of course then required. 



VII. 

VISCOSE AND VISCOID. 

The products to which these terms have been applied, 
were first prepared, in 1892, by Bevan, Beadle and Cross. 
With reference to their properties it may be expected that 
in the course of time, they will find extended application in 
the industries, because from them can be prepared cellulose 
in a perfectly pure state in the form of completely homo- 
geneous masses of any desired size, and it is possible to 
color them, or mix them with a solid body so that a plastic 
mass is obtained, the nature of which allows of the most 
diverse technical applications. 

The main point of the invention lies in the fact that a 
combination of cellulose and soda forms, on addition of 
carbon disulphide, a substance, the solution of which is 
called viscose on account of its uncommon viscosity. When 
such a soda-cellulose-carbon disulphide solution is exposed 
to the air, a gradual disintegration of the combination 
takes place, the carbon disulphide evaporating and, in many 
cases, sulphuretted hydrogen also escaping from the mass. 
The latter becomes constantly of greater consistence, and 
when all the carbon disulphide has finally evaporated, pure 
cellulose intermingled with soda, which, however, can be 
readily removed by washing, remains beliind. To the 
cellulose thus obtained the term viscoid is applied. By ex- 
posure to a higher temperature the viscose solution is in a 
very short time decomposed. 

The progress of the conversion of viscose into viscoid can 
be regulated at will by the use of a suitable temperature, 
and during this time coloring-matter or any desired pulver- 

(119) 



120 CELLULOSE, AND CELLULOSE PRODUCTS. 

ulent bodies may be incorporated witii the mass, which 
becomes constantly more thickly fluid, so that at the end of 
the operation a body is obtained resembling, as regards its 
properties, wood, horn or stone. 

If no additions are made, there is finally obtained pure 
cellulose in the form of a white mass, which in thin layers 
is, however, perfectly colorless, and this also allows of an 
entire series of special applications. A few masses which 
can be prepared from viscoid will later on be more closely 
described. 

The process for the preparation of viscose has been modi- 
fied by several technologists, but the main point remains 
the same in all the methods, namely, that soda-cellulose is 
first prepared and then converted by the addition of car- 
bon disulphide into viscoid, which is dissolved in water. 

Cellulose of various derivatives is used as raw material 
for the preparation of the viscose solution. Purified cotton 
may be employed just as well as cellulose obtained from 
wood, and cleaned scraps of cotton and linen fabrics may 
also be utilized. In paper mills, viscose is especially em- 
ployed for sizing finer qualities of paper, and for its prep- 
aration so-called half-stufi^, prepared from cotton and linen 
rags, is frequently employed, as well as waste-paper which 
must, however, be entirely free from wood-pulp. 

PREPARATION OF VISCOSE. 

For experiments on a smaller scale in the preparation of 
viscose, it is best to use as basis-materials purified cotton or 
paper free from mechanical wood-pulp, because in working 
other materials, the assistance of disintegrating and mixing 
machinery is indispensable, while the above-mentioned 
materials can be readily converted into soda-cellulose, and 
the latter into viscose. 

For working on a small scale, the cotton or paper is 
brought into a large rubbing dish and concentrated soda 
lye poured over it, the latter being distributed as uniformly 



VISCOSE AND VISCOID. 121 

as possible throughout the mass by means of a pestle. 
Enough soda 13^6 is gradually added so that for about two 
parts by weight of dry cellulose, one part by weight of 
caustic soda is used, and the mixture when finished con- 
tains in round figures, six parts of water. When the entire 
quantity of caustic soda has been added, the dish is covered 
and allowed to stand for some time so that any fibres which 
may not have been moistened, can come in contact with the 
caustic soda. The mass consisting of soda-cellulose is then 
quickly pressed out, brought into a flask and 40 per cent, 
of its weight of carbon disulphide poured over it. The 
mass soon becomes transparent and gelatinous without, 
however, becoming fluid, its viscosity being so great that it 
liquefies only when a sufficient quantity of water is added. 
By allowing the flask to stand quietly, the particles w^hich 
have remained undissolved, settle gradually on the bottom, 
and the supernatant fluid of a yellowish color becomes 
almost entirely clear. This fluid consists of a solution of 
viscose in water. 

If a layer of this solution be uniformly distributed upon 
a glass plate — in the manner photographers do with collo- 
dion — it becomes in a short time gelatinous and finally 
solid and odorless. If now the glass plate be placed in 
water, changing the latter several times, the soda is dis- 
solved and, after drying, a perfectl}'^ colorless film of struct- 
ureless cellulose can be drawn off" from the glass plate. By 
mixing certain quantities of viscose solution with coloring 
substances or pulverulent bodies, experiments on a small 
scale may also be made for the production of masses with 
fixed properties. 

PREPARATION OF VISCOSE ON A LARGE SCALE. 

For the preparation of viscose on a large scale, such cellu- 
lose as is made for paper-manufacturing purposes is gener- 
ally used, a short-fibered product with fibres 0.059, or at 
the utmost 0.079, inch in length being generally selected, 



122 CELLULOSE, ANP CELLULOSE PRODUCTS. 

because experience has shown that long-fibered cellulose 
requires a much longer time for conversion into soda- 
cellulose. Since the process proceeds in a correct manner 
only when the soda lye shows a certain degree of concen- 
tration, the cellulose should contain only a limited amount 
of water, not exceeding 50 per cent. Hence the content of 
water in the cellulose has to be accurately established, the 
quantities of further additions being determined thereby. 

The operation commences with the comminution of the 
cellulose. Small disintegrators were formerly used for this 
purpose, but at the present time the cellulose is worked in 
the same manner as for blotting paper, the knife of the 
hollander being so set as to obtain a product of as short a 
fibre as possible. The mass coming from the hollander is 
as far as possible freed from water in a centrifugal, and is 
then spread out in layers and left until it is air-dr3\ 

The quantitative proportions between cellulose and caus- 
tic soda used in practice vary within very wide limits. 
The use of more caustic soda than is absolutely necessary 
for the formation of soda-cellulose being mere waste, the 
quantity required for every fresh batch of cellulose should 
be accurately determined by an experiment on a small 
scale, because in working man}^ hundred pounds of cellu- 
lose one-half per cent, more or less of caustic soda represents 
a considerable sum. 

The proportions generally used are as follows : Air-dry 
cellulose, 25 to 33 parts ; caustic soda, 12.5 to 16 ; water, 
52 to 55. 

The caustic soda, which should always be used in the 
form of a concentrated solution, is mixed with the cellulose, 
water being gradually added, because the at first highly 
concentrated soda solution acts more rapidly than when the 
entire quantity of water is at once used. It may here be 
remarked that the quantity of water given above includes 
the water contained in the air-dry cellulose. 

The commencement of the formation of soda-cellulose is 



VISCOSE AND VISCOID. 123 

recognized by the behavior of the mass, it swelling up very 
much, and a considerable increase in the temperature also 
takes place. When the mass has acquired the appearance 
of crumbled bread it is an indication that the process is 
finished. 

In practice the preparation of soda-cellulose is effected by 
two different methods, and ever}' manufacturer, after having 
once adopted one of them, prefers it to the other. However, 
both are perhaps of equal value, and experience and practice 
play no doubt an important part in obtaining a product of 
suitable properties. According to one of the methods the 
celhilose is from the start worked with soda lye of the proper 
degree of concentration, while according to the other, an 
excess of soda lye is used, Avhich later on is removed. 

In working according to the first process, the celhilose is 
treated in a mill, similar in construction to a rag-engine 
used in the manufacture of paper for breaking up half-stuff. 
The cellulose is first for a few minutes worked by itself for 
the purpose of loosening it, and the soda lye is then allowed 
to run in in small portions at a time, a fresh quantit}' being 
only added when the first portion has been absorbed. If 
too much soda lye were at one time added the mass would 
become very slippery, and the runner of the mill would 
slide, instead of rolling, over it. 

When the total quantity of soda lye has been added the 
mill is kept in motion until the termination of the process 
is indicated by the mass becoming crumm3^ Since the 
mass may contain harder lumps, which might cause the 
formation of a non-homogeneous product, it is passed, after 
being taken from the mill, through a sieve with meshes not 
over 0.19 to 0.23 inch wide. The sifted mass is immediately 
brought into the storage vessels, which must be closed air- 
tight, though it may also be at once used for the prepara- 
tion of viscose. . 

For the preparation of soda-cellulose according to the 
other method, in which soda lye in excess is used, the cellu- 



124 CELLULOSE, AND CELLULOSE PKODUCTS. * 

lose is first mixed with about ten times the quantity of soda 
lye of 15 to 18 per cent. The lye is allowed to act until 
the operation is finished, the portion of it which has not 
been absorbed is discharged, and the mass is treated in a 
centrifugal, a certain quantity of lye being thereby regained. 
By simply mixing the cellulose with the soda lye, lumps 
are frequently formed in the mass in consequence of the 
increase in volume which takes place, and the soda-cellulose 
after coming from the centrifugal has to be especially com- 
minuted and passed through a sieve. 

SODA-CELLULOSE. 

In storing soda-cellulose prepared according to one of the 
processes described above, it will sometimes be observed 
that it becomes heated to quite a high degree. This phe- 
nomenon can only be explained by assuming that the for- 
mation of soda-cellulose is only incompletely effected in the 
apparatus used for the purpose, and that it is gradually 
effected in the storage vessels. However, by this process a 
certain quantity of heat is liberated, which by reason of 
the wood of the barrels used for storage being a bad con- 
ductor, is kept together. 

Since the quality of the soda-cellulose is impaired by this 
development of heat, and there may be even danger of a 
fire breaking out in consequence of it, certain precautions, 
given below, should be observed in storing soda-cellulose. " 

The main point in the manufacture of soda-cellulose is to 
have the entire process finished as rapidly as possible, soda- 
cellulose being a body which absorbs with avidity carbonic 
acid from the air, and to bring the product immediately 
into the storage vessels, closing the latter air-tight. 

STORING SODA-CELLULOSE. 

Soda-cellulose being a combination of but slight con- 
stanc3% only such a quantity should, as a rule, be prepared 
in one operation as can be worked into viscose in three or 



VISCOSE AND VISCOID. 125 

four days, experience having shown that a ver}'^ thickly- 
fluid viscose cannot be obtained from soda-cellulose which 
has undergone changes by long storing, the product in this 
case possessing but little viscosity. 

The injurious changes soda-cellulose undergoes appear 
the more quickly the higher the temperature is to which it 
is exposed. Hence means should be provided in every 
factory by which the product can be kept in an unchanged 
state from the moment it leaves the mill and has been 
passed through the sieve. Instead of bringing the pro- 
duct into a wooden vessel, it is allowed to fall into a large 
sheet-iron vessel which is surrounded with ice. When 
this vessel has been filled with the sifted mass, a ther- 
mometer is pushed into the center of the latter, and the 
vessel closed with a well-fitting lid. Soda-cellulose being a 
bad conductor of heat, some time is required for the mass 
to cool throughout, and it must be allowed to stand until 
the thermometer indicates a temperature of 41° to 43° F. 
The mass is then quickly packed into the storage barrels 
and the latter are placed in a cool cellar, best in an ice- 
house. The expense of the ice required is slight in com- 
parison to the loss incurred by the spoiling of a quan- 
tity of the product. In storing the soda-cellulose at such 
a low temperature larger vessels may also be used. How- 
ever, in storing the product at a higher temperature, the 
use of smaller barrels of about 220 lbs. capacity would at 
all events appear not advisable, since, as is well known, 
the heat from the outside acts more rapidly in a smaller 
vessel than in a larger receptacle. 

Comparative experiments have shown that soda-cellulose 
stored in an ice-house remained unchanged after two 
months, but its stability decreased with every degree of 
heat. A maximum temperature of 50° to 53.6° F. would 
appear to be most suitable for the storage room, and if arti- 
ficial cooling is not to be applied, the cold season of the 
year is best adapted for the manufacture of soda-cellulose. 



12G CELLULOSE, AND CELLULOSE TRODUCTS. 

However, in many countries the manufacturer is, even in 
the cold season, subject to the caprices of the weather, and 
it is therefore advisable to combine a cooling plant with a 
viscose factor3\ Soda-cellulose, which was kept at 68° F. — 
the ordinary temperature of a room — became, as a rule, so 
changed in 60 to 70 hours that it could no longer be used. 

As regards the products formed by the decomposition of 
soda-cellulose in consequence of the action of too high a 
temperature, the appearance of acetic acid (formic acid ?), 
lactic acid and acetyl-lactic acid has been established. These 
combinations, however, can only appear with the complete 
decomposition of the cellulose. Hence it appears probable 
that the alteration of the soda-cellulose commences with a 
transposition inside the molecule of the cellulose, the conse- 
quence being that a large part of the substance is no longer 
soda-cellulose, and hence cannot form the combination to 
which the term viscose has been applied. 

The unpleasant observations made in working soda-cellu- 
lose in which alteration has already commenced are of vary- 
ing nature, but the fluid lacks chiefly the great viscosity 
and adhesive power which are its characteristic properties. 
The cellulose recovered from such a thin solution possesses 
b.ut little strength, and is so brittle that it can scarcely be 
worked. 

PEEPAEATION OF VISCOSE. 

Viscose is formed by simpl}'^ bringing together at the 
ordinary temperature soda-cellulose with carbon disulphide, 
the process taking place the more rapidly the more intimate 
the contact between the two bodies. Chemically the com- 
bination formed is cellulose sulphocarbonate. It is readily 
soluble in water and on exposure to the air is decomposed 
at the ordinary temperature, cellulose in the form of a color- 
less and structureless mass being separated. At a higher 
temperature decomposition progresses with great rapidit}'. 

In preparing viscose it must be borne in mind that car- 



VISCOSE AND VISCOID. 127 

bon disulphide is a very volatile substance — its boiling 
point being at 118.4° F. — and vessels which can be closed 
absolutely air-tight have to be used. Carbon disulphide 
frequently contains small quantities of sulphur in solution 
and as this would have an injurious effect upon metallic 
vessels, apparatus entirely constructed of wood should be 
employed. 

The most suitable, and at the same time the most simple, 
apparatus for the preparation of larger quantities of viscose 
is a revolving barrel with quite a large bung-hole, which 
can be securely closed with a screw-cover. In place of a 
revolving barrel, a stationary barrel may also be used. The 
contents are mixed by means of a stirrer consisting of a 
shaft with shovel-like paddles with which the barrel is fur- 
nished. 

The proportion between soda lye and carbon disulphide 
is, by the way, 10 to 1. For 100 parts of soda-cellulose 10 
parts of carbon disulphide are used, though a small excess 
of the latter is of no importance. When both the sub- 
stances have been brought into the apparatus, the latter is 
securely closed and set in motion, being thus kept uninter- 
ruptedly until the formation of the combination is com 
plete. The time necessary for this purpose depends largely 
on the temperature ; three hours being, as a rule, required 
with a temperature of 60° F., while with one of 77° to 86° 
F., the formation of the combination may be complete in 
one hour. 

The cellulose sulphocarbonate forms a loose mass, differ- 
ing in appearance from soda-cellulose only by its pale yel- 
low color. When brought in contact with water it should 
gradually be completely dissolved. If any flakes remain 
undissolved, it may be due to two causes, one of them being 
that all the cellulose has not been converted into soda- 
cell alose, and the other, that an insufficient quantity of 
carbon disulphide has been used, or that it has acted for 
too short a time. In the first case, the mass cannot be im- 



128 CELLULOSE, AND CELLULOSE PRODUCTS. 

proved, but, in the second, an experiment may be made by 
continuing the manipulation in the revolving barrel with 
the addition of a certain quantity of carbon disulphide. 

When the proportions have been correctly chosen, a small 
excess of carbon disulphide remains, as a rule, behind. 
This may be recovered by attaching to the hollow shaft of 
the barrel a pipe ending in a coil which terminates in a 
vessel filled with ice. A small suction pipe is placed on 
the lower end of this ice vessel. The other end of the hol- 
low shaft of the revolving barrel is furnished with a small 
cock. This cock is opened and the suction pump set in 
motion while the barrel is slowly revolving, a current of air 
being thus sucked through the contents of the barrel 
whereby the excess of carbon disulphide is evaporated. 
The vapors on coming in contact with the ice are con- 
densed, and ice water and carbon disulphide run off into a 
collecting vessel placed at the lower end of the ice-holder. 

PREPARATION OF VISCOSE SOLUTION. 

For this purpose the contents of the revolving barrel are 
brought into a closed vessel which is furnished with a 
vigorously-acting stirring contrivance, and, after setting the 
latter in motion, water in small quantities is allowed to run 
in. Immediately after the first portions of water have 
been admitted, the mass commences to swell up very much, 
and would in a short time acquire such a degree of vis- 
cosity as to impede the motion of the stirrer. Hence more 
water is allowed to run in until the quantity of it admitted 
amounts to 1| times the weight of the soda-cellulose brought 
into the apparatus. 

The stirrer is kept in motion until solution is complete, 
when the viscose is immediately brought into the vessels in 
which it is to be stored or shipped. Viscose should as far 
as possible be protected from the access of air, being rap- 
idly decomposed on coming in contact with it. Viscose 
solution which is immediately to be used in factories where 



VISCOSE AND VISCOID. 129 

it has been prepared, may be kept in an open vessel of wood 
or zinc-sheet. A layer of water is carefully poured upon it 
so that no mixing of the two fluids takes place ; this layer 
of water protecting the viscose from becoming decomposed. 
When viscose solution is allowed to stand open, a thin film 
of cellulose forms in a short time on the surface, and this 
has to be removed when the viscose is to be used. 

STORING VISCOSE. 

Since viscose is rapidly decomposed by the access of air, 
as well as at a higher temperature, special precautionary 
measures have to be taken to prevent decomposition when 
larger quantities of it are to be stored. ' As is the case with 
soda-cellulose, these precautionary measures consist in shut- 
ting out the access of air, and keeping the storage-room at a 
low temperature. 

The most simple plan is to store the viscose in a sheet- 
zinc cylinder provided around its upper edge with a gutter, 
into which fits the 1| to 2 inches deep rim of a sheet-zinc 
lid. The vessel having been filled, the lid is placed in the 
gutter and the latter filled with water, thus forming a kind 
of hydraulic joint, which renders the access of air to the 
contents of the cylinder impossible. 

The stability of the viscose is the greater the lower the 
temperature of the room in which it is stored. In rooms 
having a temperature of 77° F. or more, decomposition 
takes place very rapidly ; at the ordinarj' temperature 
of a room viscose cannot be kept longer than 5 or 6 days 
without undergoing a change, and stability for two weeks 
can only be counted upon with a temperature below 50° F. 

If, however, viscose solutions are stored in a room the 
temperature of which is kept, by artificial cooling, not much 
above the freezing point of water, the viscose can be kept 
in a perfectly unchanged state for a number of weeks. In- 
dependent of the assurance of preserving the viscose in an 
unchanged state, storing it at a low temperature offers a 
9 



180 CELLULOSE, AND CELLULOSE PRODUCTS. 

great advantage in working the material. The temperature 
of the viscose when taken from the storage vessel is of course 
quite low, and as it becomes gradually higher in the normal 
warmth of the work-room, there is no difficulty whatever in 
working it at the degree of heat best adapted for the work 
in hand. 

The shipping of viscose, especially during the warm sea- 
son of the year, is connected with many difficulties, which 
can only be overcome by special precautionary measures. 
Viscose. is shipped in closed sheet-zinc vessels, and when the 
latter are in a hot summer day forwarded by railroad, there 
is great danger as regards the stability of the product, since 
the temperature of freight cars exposed to the sun frequently 
reaches 95° F. or more. Hence the viscose, cooled down to 
a low temperature, should be shipped by fast freight, and 
the vessels containing it be protected as much as possible 
from heating by wrapping them in wet cloths. 

PROPERTIES OF VISCOSE SOLUTIONS. 

The commencement of the decomposition of a viscose 
solution is first of all recognized by the mass, at first only 
viscid and of about the consistency of a gum solution, be- 
coming thicker and acquiring the consistency of a warm 
glue solution at the beginning of coagulation. As decom- 
position-progresses the mass assumes the consistency of 
jelly. By taking it in hand at the right time, the mass 
may be restored to a useful condition by adding a suitable 
quantity of water, thus making it again more thinly-fluid. 

It is probable that changes constantly take place even in 
a perfectly available viscose solution, as shown by the be- 
havior of viscose when exposed in a thin layer to the air. 
In many cases decomposition simply takes place by vapors 
of carbon disulphide escaping frora the mass, which con- 
stantly becomes more thickly-fluid, and finally nothing but 
cellulose remains behind. 

In other cases it will, however, be noticed that sulphur- 



VISCOSE AND VISCOID. 131 

etted hydrogen is evolved, and that the mass contains con- 
siderable quantities of sodium carbonate as well as sul- 
phides and trithiocarbonate. The appearance of these 
combinations can only be explained by the decomposition, 
by the action of the alkali, of a portion of the carbon disul- 
phide present. 

The decomposition of the viscose is very much influenced 
by the temperature at which it takes place. Viscose solu- 
tion exposed upon a glass plate to a temperature of but a 
few degrees above the freezing point is changed very slowly ; 
the mass constantly acquires greater consistence and a solid, 
structureless film consisting of cellulose remains finally 
behind. The higher the temperature, the shorter the time 
in which decomposition takes place and at 104° F., it pro- 
ceeds with great rapidity. When the temperature rises 
above 122° F., a homogeneous, coherent mass is no longer 
obtained, but one which here and there shows white spots 
which are produced by numerous small bubbles. At this 
high temperature decomposition takes place with such 
rapidity that the vapors evolved can no longer escape from 
the mass on account of its viscosity, but are retained in it 
like air-bubbles in rapidly freezing ice. At a still higher 
temperature, for instance, pouring the solution upon a 
highly heated plate, decomposition of the viscose takes 
place almost instantly, a mass of a very porous, spongy 
nature being obtained. 

In many cases, for instance, in using viscose for sizing 
paper, it might be desirable for decomposition to take place 
more rapidly at the ordinary temperature than usually 
is the case, and this may be done by replacing the soda in 
the viscose by ammonia. The decomposition of viscose 
prepared in this manner takes place at a much lower tem- 
perature than that of soda-viscose, and carbon disulphide 
and ammonia escape in abundance from the decomposing 
mass. As previously mentioned, the behavior of viscose in 
decomposing depends on the temperature and its age, and 



132 CELLULOSE, AND CELLULOSE PRODUCTS. 

only by long, practical experience is it possible to judge 
from the start of its action in this respect. Hence to avoid 
disagreeable occurrences it is recommended to test a small 
quantity of every fresh viscose to be worked as to its be- 
havior, and to arrange the course of the work accordingly. 

CONVERSION OF VISCOSE INTO VISCOID. 

When a 0.15- to 0.19-inch-deep layer of a viscose solution 
in a vessel is exposed to a temperature not exceeding 40° F., 
a thin film is first formed, and, by exercising care, can be 
lifted off. If this film be brought into water it redissolves, 
and therefore it consists evidently of a combination having 
some resemblance to viscose, though it appears in a solid 
form. If, however, this film be for some time exposed to 
the air it loses its solubility in water, but swells up in it to 
a jelly-like mass. If finally it be exposed for from half an 
hour to an hour to a temperature of 212° F., it has become 
entirely indiff'erent to water and behaves towards it like a 
film of nitro-cellulose. 

Except for the production of very thin films and threads, 
viscose is seldom used by itself For the preparation of 
thicker plates from viscoid — this term being applied to con- 
gealed viscose — a special method has to be adopted in order 
to obtain a perfect product. First of all it is necessary to 
know how thick the plates will be which can be obtained 
from a viscose layer of determined thickness by its conver- 
sion into viscoid, and this is ascertained by a preliminary 
experiment on a small scale. For the preparation of thick 
plates or blocks, sheet-zinc vessels of appropriate depth are 
used and filled with viscose. The vessels are then exposed 
in a room perfectly free from dust to a uniform temperature 
of 95° to 104° F. until the mass remaining in them has 
acquired the requisite quality. In order not to be incon- 
venienced by the vapors of carbon disulphide and other 
products of decomposition escaping from the mass, it is 
advisable to place the vessel in a box furnished with a pipe 



VISCOSE AND VISCOID. 133 

entering a chimney, and to keep the temperature of the box 
uniformly at the above-mentioned degree, by a few heating 
pipes. 

When a solid mass has been formed it is removed from 
the vessel and for some time heated at 212° F. Viscoid 
being a bad conductor, this heating must be continued the 
longer the thicker the plates are ; at any rate it must be 
continued till the plates when dipped in water no longer 
swell up. 

The plates are then laid in clean water, by which the 
salts contained in them are slowly dissolved, the water 
being renewed so long as soluble substances from the vis- 
coid are absorbed by it. When the work has been care- 
fully done the viscoid plates present the appearance of 
transparent glass. If the plates show here and there dull 
specks or white opaque spots, it is an indication of too high 
a temperature having been used in drying up the viscose, 
and that the mass is interspersed with small bubbles. 

BEHAVIOR OF VISCOSE TOWARDS METALLIC SALTS. 

When a viscose solution is brought together with a me- 
tallic salt, reciprocal decomposition takes place, the metallic 
oxide combining with the cellulose and the sulphocar- 
bonate, while the soda fixes the acid of the metallic salt. 
The new combinations thus formed have not yet been 
sufficiently investigated as to their availability in practice, 
though a few of them have found practical application in 
the manufacture of paper. By mixing magnesium sulphate 
with viscose, magnesium- viscose and sodium sulphate are 
obtained, and as both these salts are readily soluble in 
water, no precipitation takes place after adding the magne- 
sium sulphate. Magnesium-viscose possesses the property 
of decomposing with still greater rapidity than soda-viscose, 
which makes it very valuable for certain purposes, especially 
for sizing paper ; the sodium sulphate adhering to the de- 
composed mass being a readily soluble salt can without 
trouble be removed from the paper mass. 



134 CELLULOSE, AND CELLULOSE PRODUCTS. 

By adding to a viscose solution the solution of a salt of a 
heavy metal, insoluble viscose of the metal added . is 
formed. With the exception of the zinc combination, which 
is used for sizing in the manufacture of paper, none of these 
combinations has become of technical importance. 

The proportional quantities of the bodies which are added 
to sodium-viscose for the purpose of obtaining other varie- 
ties of viscose, vary according to the object which the 
preparations in question are to serve. Thus, for instance, 
in paper mills 9 parts ammonium sulphate, or 15 parts 
magnesium sulphate, or 18 parts crystallized zinc sulphate 
are used for every 100 parts of a 10 per cent, soda-viscose. 

PREPARATION OP VISCOSE ACCORDING TO CROSS. 

According to a process recently patented by F. Cross, the 
quantity of caustic soda required for the preparation of vis- 
cose can be reduced one-half by treating the cellulose to be 
worked previous to submitting it to the action of the alkali, 
with dilute acids, at a temperature of between 212° and 284° 
F. This is of great advantage, because on the one hand, 
with the use of large quantities of caustic soda the cost of 
producing the article is considerably greater, and, on the 
other, the large content of alkali and sulphur in viscose 
prepared according to the older method is an impediment 
to its use for many purposes. 

The preparation of cellulose according to this process 
may be effected in various ways. According to one method 
the fibrous cellulose is treated as follows : Paper pulp, half- 
stuff, rags, waste paper, etc., are for a few hours boiled with 
dilute (2 per cent.) hydrochloric or sulphuric acid ; or the 
fluid is brought to the boiling point by itself when the cel- 
lulose is introduced, boiling being constantly kept up, and 
allowed to remain in the fluid until it has been converted 
into the brittle modification. According to another method, 
the cellulose is completely saturated at the ordinary tem- 
perature with dilute (2 per cent.) hydrochloric acid. The 



VISCOSE AND VISCOID. 135 

excess of hydrochloric acid is then removed by treating the 
mass in a centrifugal, and the cellulose is completely dried 
at a temperature of between 140° and 176° F., care being 
taken that drying is uniformly eflPected. The transition of 
the cellulose to the brittle modification then takes place 
during drying. 

According to a third method given by Cross, the cellu- 
lose is for a short time treated with dilute (1 per cent.) sul- 
phuric acid in a digester under high pressure at a tempera- 
ture of between 212° and 284° F. In place of dilute 
sulphuric acid, dilute hydrochloric acid containing but J 
per cent, of acid may also be used. The quantit}^ of acid 
used should amount to five times the weight of the cellulose 
to be worked. The mass coming from the digester is freed 
from the acid fluid by washing, and pressed to reduce its 
content of water to between 50 and 40 per cent. 

The most advantageous proportional quantities of caustic 
soda and water to be used for the cellulose thus prepared 
are within the following limits : Cellulose 40 to 50, caustic 
soda 10 to 12, water 50 to 38 per cent. 

The soda lye is used in accordance with the content of 
water in the cellulose to be worked, and the further manip- 
ulation of mixing to soda-cellulose is generally effected in 
a crushing mill or other grinding contrivance, the operation 
being continued until the mass is perfectly homogeneous. 
The conversion of the soda-cellulose into viscose, and of the 
latter into viscoid, does not differ from the method previously 
described. 

PREPARATION OP VISCOSE ACCORDING TO SEIDEL. 

H. Seidel's process for the preparation of viscose differs 
but little from the one just described. According to the 
inventor's statements, 100 parts of sulphite-cellulose are for 
a few hours placed in dilute (1 per cent.) hydrochloric 
acid, the mass is then squeezed out and rinsed in water. 
It is then brought into intimate contact with a solution of 



136 CELLULOSE, AND CELLULOSE PRODUCTS. 

40 parts of caustic soda in 100 parts of water, and left to 
itself in a closed vessel for three days. One hundred parts 
of carbon disulphide are then brought into the vessel and 
distributed by stirring, when the mass is again allowed to 
repose for 12 hours. A yellow-colored solution is formed 
from which the viscose may be precipitated by alcohol or 
common salt solution. 

Viscose prepared from sulphite-cellulose dissolves with 
somewhat greater difficulty, but has the advantage of being 
lighter in color than other varieties, and can even be ob- 
tained entirely colorless. It is less suitable for the prepar- 
ation of plastic masses, but is remarkably well adapted for 
sizing paper. 

According to Seidel, transparent plates of viscose are ob- 
tained from cotton by treating cotton fabrics, according to 
the process just given, up to the period at which the addi- 
tion of carbon disulphide is to be made. Instead of adding 
the latter, the fabrics are hung in a room the atmosphere 
of which is saturated with carbon disulphide vapors, allow- 
ing them to remain for twelve hours. The rinsed fabric is 
stretched smoothly upon a glass plate, exposed for two days 
to the air, then completely dried in a drying closet, and 
finally placed in dilute hydrochloric or acetic acid. 

According to this process, plates are obtained which have 
the appearance of parchment, and by heating to 212° F., 
become so plastic that they may be given any desired 
shape. They can be bleached with chloride of lime and 
then form a perfectly colorless mass, which, when colored, 
retains its transparency. It may here be remarked that 
the process above described would seem to be of but little 
practical importance since viscoid plates can be prepared in a 
much simpler, and at the same time cheaper, manner from 
ordinary viscose by spreading a somewhat thicker layer of 
the latter upon a glass plate provided with a rim of appro- 
priate height, detaching the smooth plate from the glass 
plate, and treating it further in the usual way. The use of 



VISCOSE AND VISCOID. 137 

cellulose in the form of cotton offers no advantage, but con- 
siderably increases the cost of production. 

The process above described may, however, be utilized to 
advantage for giving a loosely-woven, thin tissue the ap- 
pearance of a close and firm fabric. For this purpose the 
washed and dried tissue is unwrapped from a roll into a 
vessel containing the soda lye, remaining in it for several 
days so that a considerable quantity of soda-cellulose may 
be formed. 

The tissue is then freed from the greater portion of 
adhering fluid b}'^ subjecting it to strong pressure between 
two rolls. It is next loosely hung up in a chamber, the 
door and windows of which can be closed air-tight. A 
shallow vessel filled with carbon disulphide is placed upon 
the floor of the chamber and the latter closed air-tight. 
The tissue is allowed to remain in the chamber until the 
quite dark yellow color it acquires by the action of the car- 
bon disulphide remains constant. 

The chamber is then opened, thoroughly aired and the 
tissue is removed when it has again become white and per- 
fectly dry. It is then taken through a bath of dilute (2 to 
3 per cent.) hydrochloric acid, washed and dried in a 
stretched state, this being necessary as otherwise it would 
shrink very much. 

Tissues thus treated appear nearly twice as thick as orig- 
inally, feel firm to the touch, and possess remarkable 
strength. These phenomena may be explained by the 
change the separate fibres of which each thread consists 
have undergone. Every fibre on its surface and to within 
a certain depth has been converted into viscose which pen- 
etrates the entire mass like varnish. The tissue taken from 
the carbon-disulphide chamber acquires, when moistened 
with water, a quality reminding one of a thoroughly soaked 
animal skin. When the viscose is again decomposed the 
separated cellulose cements the finest fibres of the threads 
most intimately together, and this explains the compact ap- 



138 CELLULOSE, AND CELLULOSE PKODUCTS. 

pearance, firm feel, and great strength of the tissues thus 
treated. 

PREPARATION OF CHEMICALLY-PURE CELLULOSE-SULPHO- 
CARBONATE (vISCOSE). 

Viscose prepared according to the ordinary method is not 
a pure product consisting solely of the combination cellu- 
lose-sulphocarbonate, but always contains certain quantities 
of sodium carbonate, thiocarbonic acid and carbon disul- 
phide. According to the process of the Viscose Syndicate 
Limited, it can be freed from these bodies by treating the 
raw product with weak acids — lactic, formic or acetic acid 
— in excess, whereby the viscose is not changed, but the 
above-mentioned foreign bodies are rendered harmless. The 
fluid is then mixed with a water-withdrawing body, such as 
alcohol or common salt solution, and entirely pure viscose 
which separates as a mass of leathery appearance, is thus 
obtained. The product is again washed with dilute alcohol 
or common salt solution, and dried. 

Pure viscose obtained in the above-described manner, is 
a neutral, colorless and odorless mass, which rapidly dis- 
solves in water without leaving a residue, and is especially 
well adapted for sizing paper and fabrics. 

USES OF VISCOSE. 

Viscose, or viscoid prepared from it, is already used to a 
considerable extent in various industries, and it may be 
supposed that both these substances will find various tech- 
nical applications. Viscoid, as previously explained, is 
simply pure cellulose, and it being in a certain measure 
available in a fluid state in viscose, it is possible to obtain 
the cellulose in a solid form and to give the article thus ob- 
tained any desired color. 

Quite bulky bodies can be prepared from viscose, and 
any desired pulverulent substances may be incorporated 
with the mass as it becomes solid, so that the articles pro- 



VISCOSE AND VISCOID. 139 

duced in this manner resemble, as regards their appearance 
and partially their properties also, horn, ivory, wood or 
stone. In the same manner transparent plates or very thin 
leaves may be prepared from viscoid, or they may be ob- 
tained in the form of exceedingly fine threads well adapted 
for spinning. 

From what has been said, it seems more than probable 
that viscose, as well as viscoid, may in the future strongly 
compete with celluloid, the cost of producing it being, on 
the one hand, less, and on the other, it is not nearly as 
inflammable as celluloid, the great combustibility of the 
latter requiring constant precaution in handling it. 

It would be impossible to give a detailed description of 
all the uses to which viscose and viscoid might be applied. 
However, the suggestions made here will be sufficient to 
guide the practical man in the preparation of masses with 
determined properties. 

USE OF VISCOSE IN THE MANUFACTURE OF PAPER. 

Since by the decomposition of viscose there remains be- 
hind a substance consisting of a product, which has to be 
designated as paper in the actual sense of the word, no 
better sizing-agent for paper can be imagined. In view of 
the good qualities of paper sized with it, the use of viscose 
for this purpose lias been widely adopted in the manufac- 
ture of paper, and large quantities of it are used. 

Although soda-viscose may be directly used for sizing 
paper, it is at present employed only in exceptional cases, 
the removal of the considerable quantities of alkaline salts 
which pass into the paper mass being an unpleasant 
operation. 

In place of soda-viscose, ammonium viscose, and the pre- 
viously-mentioned compounds of viscose with magnesium 
or zinc, are at present used, these combinations possessing 
the advantage of decomposing still more rapidly than soda- 
viscose. In addition to cellulose, ammonium viscose and 



140 CELLULOSE, AND CELLULOSE PRODUCTS. 

magnesium viscose in decomposing yield throughout com- 
binations soluble in water, which can be readily removed 
by washing from the paper mass. Furthermore, in the 
decomposition of these varieties of viscose, a far less 
abundant separation of carbon disulphide takes place than 
is the case with soda-viscose, as well as with zinc-viscose. 
A further advantage of the use of ammonium or magne- 
sium viscose, as well as of zinc-viscose, is that a much 
smaller quantity of alum is consumed than is otherwise the 
case. 

Papers prepared with viscose are distinguished by a 
firmer feel and besides, by the addition of this substance^ 
great strength and extensibility are imparted to them. 

Viscose may be applied to all kinds of paper, to the 
coarsest qualities of wrapping paper as well as the finest 
varieties of writing paper. 

As shown by exact experiments, excellent results have 
been obtained by the application of viscose as a size to 
wrapping paper of which considerable strength is demanded, 
the breaking length as well as the elongation being in- 
creased 30 to 50 per cent. 

Thorough experiments in this respect have been made by 
the Versuchsanstalt at Charlottenburg, and the figures 
given below show plainly how^ the qualities of the papers 
are affected by an addition of viscose : 

Breaking Elongation 

Variety of paper. length in .^ ^^^ ^^^^_ 

meters. 

Brown wrapping paper from steamed wood 3575 1.80 

Same, sized with 4 per cent, of viscose 4750 3.00 

Brown wrapping paper from steamed wood 3200 0.90 

Same, sized with 4 per cent, of viscose 4650 2.40 

Brown wrapping paper from steamed wood 2225 1.40 

Same, sized with 4 per cent, of viscose 2925 1.97 

If fine qualities of paper, the beautiful, pure-white color 
of which is of importance, are to be sized with viscose, care 



VISCOSE AND VISCOID. 141 

must be taken to use a product of a very light color, other- 
wise the paper acquires a very noticeable yellowish tinge. 

VISCOSE IN THE MANUFACTURE OF WALL PAPER. 

In a similar manner as in cloth printing, viscose may be 
directly used in the manufacture of wall paper as a thick- 
ening agent for the printing colors employed for producing 
the designs upon the wall paper. As compared with the 
ordinary thickening agents, viscose has the advantage that 
the colors printed with it adhere far more firmly to the 
paper than is the case with other colors which frequently 
stick so badly as to be effaced by slight rubbing. 

The use of viscose is of special advantage in the manu- 
facture of the so-called flock paper, which is made by sifting 
upon sized spots of the wall paper finely comminuted colored 
wool and, after drying, removing the excess of wool dust. 
From most of the flock papers the larger portion of the wool 
can be readily removed by vigorous rubbing with a brush, 
but if the paper be printed with viscose and immediately 
covered with wool dust, the latter cannot be removed. Me- 
tallic bronze, aluminium powder, etc., triturated with vis- 
cose to a printing color and printed upon the paper, look 
like gilding and silvering and retain for years their metallic 
appearance. 

Even wall paper, made in the ordinary way, if coated, 
when finished, with viscose solution acquires thereby the 
beautiful lustre characteristic to pure cellulose, and besides, 
it may be cleansed with a sponge moistened with water, 
solution of soap or soda without damage to its beautiful 
appearance. Wall paper which in the course of time has 
suffered from smoke and dust may by this treatment be 
restored to its original beauty. Washing may be repeated 
as often as desired, because the thin layer of cellulose upon 
the paper is perfectly water-proof and indiff^erent towards 
water and soap. 

Imitations of leather and velvet hangings can in no 



142 CELLULOSE, AND CELLULOSE PRODUCTS. 

other way be made so beautiful and durable as with the 
use of viscose. By printing with viscose upon leather- 
brown paper, gold or silver bronze, and then coating its 
entire surface with viscose, it can, while still moist, be pro- 
vided with raised or depressed designs so that in appearance 
the finished wall-paper cannot be distinguished from gen- 
uine leather hangings. 

By printing designs of a certain form upon different 
places of the paper and covering them with wool powder of 
an appropriate color, then printing other places with vis- 
cose covering them also with different-colored wool powder, 
and thus continuing the operation, wall paper may be pro- 
duced having the appearance of velvet hangings of a 
determined ground color with variously-colored flowers, 
leaves, ornaments, etc., woven in. It is advisable to pass 
wall paper made in this manner with the lower non-printed 
surface down, over a heated roll with such rapidity that 
the viscose layer is during a few seconds heated to 212° F. 
By this heating the viscose becomes perfectly insoluble and 
the wall paper can without risk be rolled up. 

The examples given above suffice to show the important 
role viscose is likely to play in the manufacture of wall 
paper. 

VISCOSE IN CLOTH-PRINTING. 

In cloth-printing viscose may be used in various ways, 
namely, as a so-called resist and as a thickening and fixing 
agent for certain coloring matters. If a tissue of sheep's 
wool or silk be printed with various-colored designs by 
means of a viscose solution of appropriate strength, and the 
tissue be then passed over hot rolls, the proper places 
will be covered and impregnated with cellulose. The 
tissue may then be dyed in a dye-bath which yields its 
coloring matter to wool and silk, but not to cellulose, the 
result being a tissue showing a white design upon a colored 
ground. 



VISCOSE AND VISCOID, 143 

If the printing color be prepared by stirring the finely 
pulverized coloring matter into thick viscose solution and 
the tissue be printed With it, it is only necessary for fixing 
the color in the most durable manner, to pass the printed 
tissue over heated rolls, the color being then imbedded in a 
layer of cellulose and cannot be removed. 

Viscose solution can to great advantage be used for mark- 
ing fabrics in mills, as well as a substitute for ink for mark- 
ing household linen, etc. For this purpose a viscose solu- 
tion sufficiently thickly-fluid to yield sharp impressions with 
a rubber stamp is used, a durable coloring matter being in- 
corporated with it, finely-divided carbon in the form of 
lamp-black being most suitable as it is not dissolved by any 
known body. The tissues are marked with the assistance 
of the rubber stamp and after drying in the air, the color 
is fixed by passing a hot flat-iron over the mark. The car- 
bon is then enclosed by cellulose, and the color is not only 
upon the surface of the tissue but has penetrated it through- 
out and is, therefore, indestructible. Even an attempt to 
dissolve the layer of cellulose enclosing the carbon, by treat- 
ment with cuprammonium solution, would result only in 
making the marking somewhat paler and less distinct, but 
it would be impossible to destroy it entirely, the particles of 
carbon adhering so tenaciously to the individual fibres of 
the tissue that they cannot be removed. 

In place of carbon any desired pulverulent coloring mat- 
ter may be used, but care must be taken that it is of such 
a nature as not to be changed by free alkali or carbon disul- 
phide. 

VISCOSE AS A SIZE OR DRESSING. 

The size or dressing generally used in the textile industry 
consists, as a rule, of gum-like substances, a paste prepared 
from various kinds of starch being partially employed for 
the purpose. However, these agents are entirely removed 
by washing the fabrics once or at the utmost twice, and the 



144 CELLULOSE, AND CELLULOSE PRODUCTS. 

latter lose their good appearance and firm feel ; as well as 
the lustre given to ihem by the size or dressing. 

In addition the weight of the fabric is considerably de- 
creased, because the pipe clay or heavy spar which had been 
added as a loading agent to the size, has also been washed 
out. 

Viscose offers a means of sizing tissues in such a manner 
that they retain, even after repeated washing, their smooth- 
ness and lustre, and lose nothing in bod}^ Sizing with vis- 
cose is effected in various ways according to the object w^hich 
is to be attained. 

The simplest mode of sizing consists in drawing the tissue 
from a drum upon which it has been wrapped and passing 
it through a vat filled with viscose solution of suitable con- 
centration. By passing the wet tissue between two rubber 
rolls set close together, fixed above the vat, the excess oi 
fluid is removed and falls back into the vat. After drying, 
the tissue appears sized with a layer of viscoid, the thick- 
ness of which depends on the concentration of the viscose 
solution used. By passing the tissue again through the 
viscose solution and repeating the operation, under special 
conditions, for the third time, sizing is finally eff'ected to 
such an extent that all the pores of the tissue are closed 
with cellulose, and it is just as water-proof as if it had been 
impregnated with rubber. 

Loading agents may also be added to the viscose, thus 
imparting great weight to the tissue, which it, however, re- 
tains when washed, because the particles of the loading 
a,gent are cemented one to the other, as well as to the fibres 
of the tissue, by the insoluble cellulose. 

To impart to the tissue treated wdth viscose great smooth- 
ness, and at the same time a beautiful lustre, it is advisable 
to arrange the finishing machine so that the tissue after 
having been pressed out by the rubber rolls, passes under 
high pressure through two polished, hollow rolls heated 
b}'' steam. By this heating, the viscose is instantly con- 



VISCOSE AND VISCOID. 145 

verted into insoluble cellulose and the latter is forced into 
the separate depressions of the tissue, thus imparting to 
the latter a smooth and lustrous surface. 

PREPARATION OP LEATHER-LIKE BODIES BY MEANS OF 

VISCOSE. 

The results of all the attempts to produce a substance 
with such physical properties, especially as regards tenacity 
and strength, that it would answer as a substitute for leather, 
have to be accepted only conditionally, and all products 
commended under the names of artificial leather or substi- 
tutes for leather have to be viewed with a certain mistrust 
as regards their durability and power of resistance. The 
reason for the failure to produce a substance which might 
satisfactoril}^ replace leather, is found in the nature of the 
latter material itself 

Leather is the portion of the animal skin to which the 
term corium is applied. When a piece of corium is exam- 
ined under the microscope, it will be seen to consist of in- 
immerable fibres twisted together, forming an extremely 
tough substance. By the tanning process the fibres of the 
corium are coated with a tanning substance which prevents 
the individual fibres, in drying, from adhering firmly to- 
gether as is the case in raw hide, the latter drying to a 
hard horny substance, while leather remains flexible. 

Hence, if a substance is to be produced which shall to a 
certain extent possess the characteristic strength, tenacity 
and durability of leather, it has to be prepared in such a 
manner that in structure it approaches that of leather. 
The main point is, therefore, to use a tissue of great 
strength and tenacity, and to envelop its individual fibres 
with a substance possessing also great strength and tenacity. 
With reference to these properties, viscose, or viscoid formed 
from it, plays, as will be directly shown, an important part, 
there being no other known body so suitable for the purpose. 

B^ence, in order to produce a substance which as regards 
•10 



146 CELLULOSE, AND CELLULOSE PRODUCTS. 

its properties, is to resemble leather as closely as possible, a 
tissue of suitable quality has to be throughout saturated 
with viscose. 

Since in this manner masses may be prepared which re- 
semble the finest qualities of glove leather, as well as others 
which come up to sole leather, great care will have to be 
bestowed in the commencement of the operation upon the 
fabric to be manipulated. For very thin masses, which, as 
regards their properties, are to resemble glove leather, 
closely-woven cotton fabrics are very suitable, and as the 
strength of ever}'- kind of tissue is considerably impaired by 
bleaching, it is advisable to use only unbleached tissues 
except in case the material to be prepared is to be of a pure 
white color. For the imitation of thicker varieties of 
leather, such as uppers for shoes, a coarser fabric of strong, 
unbleached linen may be employed, as well as a tissue of 
very tough Manila hemp. Finall}^, for the imitation of 
the heaviest varieties of leather, thick fabrics of very tough 
fibres are used. Such fabrics should be prepared by com- 
bining the finest fibres by doubling to coarser fibres which, 
when interwoven, yield a tissue of special strength and 
tenacity. 

In working up these various fabrics into leather-like 
masses, they are throughout saturated with viscose solution 
and made uniform by subsequent mechanical treatment, 
care being taken to keep the structure of the fabric entirely 
in the back ground, giving the material as far as possible 
the appearance of leather. 

The viscose solutions used for impregnating the tissues 
should not be too thinly-fluid, a solution containing about 
20 per cent, of viscose being probably most suitable. The 
use of a more highly concentrated solution would not seem 
to be advisable, because it is then so thickly-fluid as to 
penetrate only with great difficulty into the interior of the 
fabric. Entirely satisfactory results are only obtained when 
the tissue has been saturated throughout its entire thick- 



VISCOSE AND VISCOID. 147 

ness, so that on examining with a magnifying glass the 
cross section of the finished product, the centre presents the 
same appearance as the portions nearer the surface. 

The first step in the operation is the removal of all 
moisture from the fabric by drying it thoroughly, best by 
means of hot air. It is then placed in a box, closed air- 
tight, in which it remains until cooled to the ordinary 
temperature, and ready for impregnation. The object of 
this drying is to open the pores of the fabric so that it can 
be readily penetrated by the viscose solution. 

Imitations of leather being, as a rule, colored, dyeing is 
effected at the same time as impregnation, the appropriate 
coloring matter being added to the viscose solution, the 
quantity of coloring matter required for the various kinds 
of fabrics being determined by experiments. Thick fabrics 
require less coloring matter than thin ones, because by 
reason of the fibres in the body of the tissue being also 
colored, the coloration on the surface appears more vivid 
than is the case with thin fabrics. 

The vat containing the viscose solution should on one 
side be provided with an opening for the entrance of the 
fabric winding off" a roll. The fabric is carried below the 
level of the fluid by three rolls revolving with ease. Over 
the second of these rolls is fixed a pair of rolls so arranged 
that the distance between the two rolls can at pleasure be 
decreased or increased. This pair of rolls is set to corre- 
spond with the thickness of the fabric so that after the 
latter has been impr-egnated with viscose solution, it is only 
pressed out sufficiently to throw off* the excess of fluid 
adhering to it, which falls back into the vat. 

The fabric is passed through the viscose solution with 
sufficient rapidity to allow of its being saturated through- 
out its entire thickness. The rate of speed must be slight 
for thick fabrics, and has to be determined by direct ex- 
periments. The fabric coming from the impregnating vat 
is passed through rolls heated to between 122° and 140° F., 



148 CELLULOSE, AND CELLULOSE PRODUCTS. 

being slightly squeezed thereby wilhout being actually 
pressed. Heating to the above-mentioned temperature is 
best effected by hollow rolls heated by steam constantly 
passing through them. During the passage of the fabric 
between these heated rolls, the conversion of viscose into 
viscoid takes place, one hot pair of rolls being, as a rule, 
sufficient for thin fabrics, while for thick fabrics a second 
or third pair of rolls will have to be used. 

In place of using heated rolls, the fabric may be simply 
passed over loosely-lying rolls while a current of hot air as- 
cends from beneath, the viscose being, in this case, also de- 
composed. 

As has been previously explained, b}^ the decomposition 
of the viscose, vapors of carbon disulphide and other gases 
are constantly disengaged. To protect the workmen from 
these injurious vapors, the rolls through and over which the 
fabrics pass, should be placed in a closed box, and the latter 
be connected with a ventilator, which constantly sucks air 
into the box and carries it off. It is advisable to connect 
the ventilator to a fire-box in which the carbon disulphide 
vapors are burned to sulphurous and carbonic acids. 

When working on a large scale, it will certainly pay to 
recover and condense the carbon disulphide vapors. For 
this purpose provision has to be made for a long coil placed 
in a vessel filled with cold water, in which the warm air 
and the vapors carried along with it are first cooled to the 
ordinary temperature. From this preparatory cooler, the 
vapors are driven into a vessel filled with ice, in which the 
carbon disulphide vapor is condensed and runs off with the 
ice water. 

The fabrics having been carried through the heated rolls 
or over a current of hot air, are next exposed to strong 
pressure by being passed between smooth rolls, in order to 
give them an entirely smooth surface. They are then re- 
peatedly washed in water to free them from alkali, and are 
finally dried in the air or in artifically-heated rooms. 



VISCOSE AND VISCOID. 149 

In working thick fabrics, one impregnation with viscose 
sohition is frequent!}^ found insufficient to saturate them 
throughout tlieir entire thickness. Such fabrics having been 
passed through tlie heated rolls and cooled to the ordinary 
temperature, are subjected to another treatment with viscose 
solution, the operation being exactly the same as previously 
described. 

The fabrics impregnated according to the process given 
above are now in the following condition : All the fibres of 
the fabric are enveloped by cellulose and the empty spaces 
between the separate threads and fibres are also filled with 
it, so that the whole represents quite a uniform mass of cel- 
lulose. However, the portion of the mass belonging to the 
fabric is, in consequence of its structure, exceedingly tough 
and strong, it having acquired these properties in a still 
higher degree by being enveloped and cemented by the 
cellulose. It will be seen that such a fabric, as regards its 
structure, may be compared with leather, the fibres repre- 
senting the skin tissue, while the cellulose which envelops 
them serves for their consolidation and reinforcement. 

The impregnated fabrics, when washed and again made 
air-dry, possess quite a high degree of elasticity and a cer- 
tain softness, and can without difficulty be further worked 
by mechanical means. By passing them through brightly 
polished rolls capable of producing great pressure, they ac- 
quire a very smooth surface and high lustre. After going 
through these rolls they may be passed through others en- 
graved in various ways, for instance, for the imitation of 
morocco leather. When coloring has been properly done, 
such imitation can scarcely be distinguished from the gen- 
uine product. 

However, success in giving a .fine appearance to an 
article to be used, is of onl}' secondary importance, since by 
coloring and pressing paper it may be given a striking re- 
semblance to morocco leather. But imitations of leather 
made according to the process given above, have in addition 



150 CELLULOSE, AND CELLULOSE PRODUCTS. 

to appearance another valuable property, namely, strength 
and tenacity of substance. A piece of leather may be torn 
with greater ease than a piece of fabric of the same thick- 
ness impregnated with cellulose. 

Thick fabrics impregnated with cellulose may be used for 
shoe soles, since they have the advantage over leather soles 
of not becoming soft when exposed for a long time to damp- 
ness and shriveling to a hard mass as is the case with 
leather which by the action of moisture is deprived of a 
large portion of its content of tannin . Impregnated fabrics 
being entirely indifferent towards water are only gradually 
destroyed by the mechanical wear and tear in using the 
shoes. 

Leather belts for machines are, as is well known, quite 
expensive, as they have to be made of the heaviest and most 
carefully tanned qualities of leather. They may, however, 
be advantageously replaced by belts made of very strong 
fabrics impregnated with cellulose. Such belts up to 0.39 
to 0.59 inch thick are produced by impregnating thinner 
fabrics and cementing them together with viscose solution. 

In the above explanations, the principal elements have 
been given which must be adhered to in the preparation of 
imitations of leather in order to obtain satisfactory results, 
and by observing them it will not be difficult for a manu- 
facturer who takes up the subject, to prepare various pro- 
ducts which possess the character of the leather to be 
imitated, and are distinguished by considerable strength. 

However, not only tissues can be converted into leather- 
like masses, but also fabrics of a felt-like nature, such as 
felt itself, further felted cotton, and pasteboard. 

When ordinary pasteboard prepared from mechanical 
wood-pulp be throughout saturated with viscose solution 
and then, under constantly increasing pressure, passed be- 
tween smooth rolls, a mass is obtained which in hardness 
considerably surpasses the best quality of pressing-board, 
and, as regards tenacity and elasticity, can only be com- 



VISCOSE AND VISCOID. 151 

pared with very hard wood. It can be worked with all 
kinds of wood-working tools. On the other hand, it can, 
while still wet, be pressed into any desired form by suitable 
dies, and thus plates may be produced which equal in ap- 
pearance carved wood, and may to advantage be utilized in 
the manufacture of furniture. By the use of engraved 
plates which may also be provided with high reliefs, book 
covers of elegant appearance may be produced from paste- 
board thus prepared, these book covers having, independent 
of their cheapness, the advantage of being almost inde- 
structible. 

Since paste-board plates only 0.19 inch thick, possess, 
when impregnated with cellulose, a strength and power of 
resistance equal to that of quite thick boards, they would 
seem to be an excellent material for the construction of 
portable houses, such as are required for scientific expedi- 
tions, for the erection of observatories upon high mountains, 
etc. 

Such plates can be rendered fire-proof by treating them, 
while still moist, with alum solution, and then with water- 
glass solution, so that a house constructed from this light 
material can scarcely burn down. 

Genuine felt consists of tangled animal hair combined by 
fulling and beating to a quite solid, and at the same time 
porous, mass. By reason of its porous nature it can be 
readily impregnated with fluids. Felt plates impregnated 
with viscose solution completely retain their flexibility and 
suppleness, and being waterproof, may be used for hats, 
clothing, tents, etc. If, previous to their being treated with 
viscose solution, they are soaked in a saturated solution of 
borax in water, and then thoroughly dried, they become 
absolutely indestructible, the rotting of the felt by repeated 
exposure to moisture being prevented by the highly anti- 
septic properties characteristic of boric acid. Hence felt- 
plates prepared in this manner can be laid directly in the 
ground as a support for heavy machinery, and thus the 



152 CELLULOSE, AND CELLULOSE PRODUCTS. 

noise of the latter, when resting upon an unyielding founda- 
tion, can be almost entirely obviated- 

VISCOSE IN THE MANUFACTURE OF ARTIFICIAL FLOWERS. 

For the manufacture of imitations of flowers, leaves, etc., 
variously-colored stuffs, as well as paper, are used, the sub- 
stances being appropriately shaped, then painted, and, if 
required, varnished. Although, as regards artistic execu- 
tion, such artificial flowers are beautiful, they delineate 
only in a very incomplete manner the appearance of natural 
flowers and leaves. 

Great progress was made by the introduction of celluloid 
in the manufacture of artificial flowers as this material can 
be readily colored any shade, and moulded into any desired 
form. The high lustre peculiar to articles of celluloid had, 
in this case, the effect of still further increasing the beauti- 
ful appearance of such artificial flowers. But they are un- 
fortunately quite expensive, and possess the farther disad- 
vantage of being extremely inflammable. 

However, in viscose the manufacturer has at his disposal 
a material which deserves consideration, it being not only 
very cheap, no more inflammable than ordinary paper, and 
possesses other advantages which make it very suitable for 
the object in question. The mode of application in the 
manufacture of artificial flowers would probably be to satur- 
ate thin, porous tissue-paper with appropriately-colored vis- 
cose, and to cut out the flowers, leaves, etc., by means of 
heated dies. By contact with the heated die, the viscose is 
rapidly changed to viscoid, and the leaves, etc., retain ex- 
actly the shape given to them by the dies. The leaves are 
smooth and lustrous and, of course, have all the properties 
belonging to viscoid. They ma}^ be immersed in water 
without losing their shape or suffering au}^ other injury, 
and when they have become unsightly by dust, they may 
even be cleansed by means of an atomizer and water. 

For especially delicate artificial flowers, pure viscose may 



VISCOSE AND VISCOID. 153 

be used by allowing a thick viscose solution to dry upon 
glass plates to thin plates and making the leaves, etc., from 
the latter. By adding sufficient quantities of coloring 
matter to the viscose solntion, colored, transparent leaves of 
viscoid are obtained which, when worked into flowers, pro- 
duce a peculiar effect resembling that seen in glass 'flowers. 

VISCOSE IN PHOTOGRAPHY. 

Some kinds of photographic apparatus are so arranged 
that the picture is taken upon a transparent film, instead 
of upon a glass })late. Such a film can be produced of any 
length and wound upon a roll, and the use of such a pho- 
tographic apparatus is very convenient, especially in expe- 
ditions, as it requires but little space, and a large number 
of pictures can be readily taken. 

At present the films are almost exclusively made of 
celluloid membranes, which, however, are not so well 
adapted for the purpose as viscose, the latter being less in- 
flammable, and less sensitive to moisture and heat than 
celluloid. 

The preparation of films from viscose is a ver}'- simple 
matter. The length of a film being generally such that 
twelve pictures can be taken with one roll of it, a piece of 
plate glass corresponding in length to that of the roll of 
film has to be procured, allowing in addition a few centi- 
meters for the portion of the film secured to the I'oll. The 
film being, as a rule, larger in width than in thickness, the 
plate glass should be wide enough to allow of a large film- 
plate being at one time made, which is then cut up. 

The plate-glass is surrounded by a metal frame project- 
ing a few millimeters above it, its object being to prevent 
the viscose solution from running off the plate-glass. The 
latter is placed upon a stand provided with a ball-joint 
capable of being turned by friction, so that the plate-glass 
can be readily set in a level position. 

The viscose solution used for the preparation of films 



154 CELLULOSE, AND CELLULOSE PRODUCTS. 

should be of such concentration that, when poured m a 
layer of a fixed depth upon the plate-glass, it yields, after 
drying, a membrane of sufficient thickness ; this can be 
readily ascertained by a few experiments. The viscose 
solution is poured upon the plate-glass by commencing in 
one corner of the latter, care being taken that no bubbles 
are formed, and as the fluid spreads out over the plate-glass, 
pouring is continued until the entire surface of the plate- 
glass is uniformly covered. 

The plate-glass is then left standing without being 
touched until the viscose layer is entirely congealed. It is 
then taken ofi" and heated upon a plate of aluminium sheet 
to 212° F., until it has become insoluble. It is then 
washed with water and completely dried in the air. The 
large plate of viscoid, which should have the appearance of 
colorless glass, is then cut up into strips of film of suitable 
length, and the latter are treated with chemicals to form a 
layer sensitive to light upon their surfaces. 

VISCOID MASSES. 

If a viscose solution be allowed to stand quietly at the 
ordinary, or a somewhat higher, temperature, it decomposes 
slowly, and a plate remains behind, the thickness of which 
depends on the depth of the original viscose solution. In 
order to obtain homogeneous viscose masses free from 
bubbles, the decomposition of the mass should not be has- 
tened by heating, as otherwise the vapors and gases escap- 
ing from the mass after it has already become thickly-fluid, 
would cause the formation of bubbles in it, such as may be 
observed in ordinary glass. If, on the other hand, the 
mass is allowed to stand at the ordinary temperature until 
it has acquired the consistence of solid jelly, it maybe care- 
fully lifted from the vessel containing it and placed upon a 
glass plate, the latter being allowed to lie in a place free 
from dust until the mass is entirely solid. It is then slowly 
heated to 212° F., so that it becomes heated throughout, 



VISCOSE AND VISCOID. 165 

and then placed in water for the purpose of dissolving the 
salts present. By exposing such a block to a strong pres- 
sure, allowing it to stand under it for some time, a body is 
obtained which, in appearance, does not much differ from 
a block of glass. 

This pure viscoid may be worked with all kinds of tools. 
It can be sawed, drilled and worked in the lathe, and forms 
an excellent material for the manufacture of various fancy 
articles. If a coloring matter insoluble in water has been 
added to the viscose solution, the viscoid also appears 
colored. 

Since by mixing viscose with various indifferent bodies, 
masses may be prepared which present a pleasing appear- 
ance, and are much cheaper than pure viscoid by itself, 
they may be advantageously used for the production of 
numerous small fancy articles. When properly made they 
present almost exactly the same appearance as celluloid 
articles, but are much cheaper and not so inflammable. 

Viscose possessing great viscosity, considerable quantities 
of foreign bodies can be incorporated with it and the result- 
ing viscoid masses be nevertheless very strong, and of beau- 
tiful appearance. There are a large number of substances 
which may be used for filling viscoid masses, and in fact 
every kind of pulverulent body which is chemically indif- 
ferent to viscose may thus be employed. For the preparation 
of white masses there are, for instance, available, pulverized 
chalk, plaster of Paris, magnesium carbonate, zinc white, 
powdered talc (soapstone powder) and pulverized heavy 
spar, or preferably artificially-prepared heavy spar, the so- 
called permanent white, which is an extremely delicate 
powder. According to the substance used, there will be 
considerable difference in the resulting masses as regards 
weight, and partially also as regards lustre. Masses of a 
pure milk-white color and of comparatively slight specific 
gravity can be produced with the use of magnesium car- 
bonate, the latter being a pure white powder of very slight 



156 CELLULOSE, AND CELLULOSE PRODUCTS. 

specific gravit3^ Masses prepared witli pulverized chalk or 
plaster of Paris, though light, are heavier than magnesium 
masses. 

The lightest viscoid masses of a white color are prepared 
by mixing with the viscose as a filling-substance bleached 
cellulose made from wood by the sulphite or soda process. 
A product of not quite such a pure white color, but never- 
theless of nice appearance, is obtained with the use of 
mechanical wood-pulp prepared from a white wood, for 
instance, aspen ; such masses have a very slight yellowish 
tint. 

Since viscose solution may be colored as desired, the 
white basis-masses given above may be used for the pre- 
paration of colored viscoid masses, though the latter may 
also be obtained by mixing with the white pulverulent 
filling substances other colored powders. 

Viscose solutions, even if quite dilute, possess a consider- 
able degree of viscosity, and the preparation of homogeneous 
masses with the use of filling-substances presents certain 
difficulties, uniform mixing of the solution with the pow- 
ders being only accomplished b}' long-continued manipula- 
tion. Besides, the various powders act diflcrently in this 
respect towards viscose, and it is advisable first to make 
experiments on a small scale. For this purpose a fixed 
quantity of dilute (at the utmost 10 per cent.) viscose solu- 
tion and a fixed quantity of the powder to be used for 
filling are employed, for instance, 1 quart of viscose and 22 
lbs. of powder. Pour the viscose into a large, round vessel, 
smooth inside, for instance, a porcelain dish, and while one 
workman constantly stirs the viscose, another one pours the 
powder in a fine jet into the fluid until a thick paste is 
formed, which cannot be further worked with the stirrer. 

This paste is rolled out on a smooth plate — a marble slab 
being very suitable for the purpose — and the plate thus 
obtained is folded over and again rolled out, the operation 
being repeated until a uniform mass is obtained which is 



VISCOSE AND VISCOID. 157 

still sufficiently plastic that, when subjected to quite a 
strong pressure in a mould, all the elevations and depres- 
sions are reproduced. The moulded articles are allowed to 
stand quietly until perfectly dry. The quality of these 
test-pieces furnishes accurate information regarding the 
properties of the mass. 

A viscoid mass of the proper quality should possess beau- 
tiful lustre, and be so hard and solid that it can only be 
broken with difficulty by A'igorous blows with a hammer. 
When the mass breaks under the hammer into several 
pieces, and consequently is brittle, it is indicative of too 
large a quantity of filling-substance having been used. In 
this case the fractures are very uneven, dull and lustreless, 
while, on the other hand, the fracture of a mass containing 
not too large a quantity of filling-substance should be con- 
choidal, with sharp, smooth edges, and lustrous. 

When the quality of the test-mass is found to come up 
to the standard, the composition of the mass for the prepa- 
ration of larger quantities of it can be calculated from the 
amount of filling-substance and viscose solution used. 

For the preparation of larger quantities of viscoid masses 
special mechanical contrivances have to be employed which 
allow of the thorough kneading together of the fluid and 
the powder. Mixing or klieading machines, such, for in- 
stance, as imitate kneading bread-dough by hand, are best 
adapted for the purpose, since with such machines any 
desired power may be applied. Mixing and kneading ma- 
chines of this kind performing excellent work are, lor in- 
stance, constructed by Werner and Pfleiderer, the work of 
thorough mixing being effected by an implement of peculiar 
construction, the so-called mixing paddle. A large number 
of machines of this kind are at present in use in bread 
bakeries, paint factories — in fact in all kinds of establish- 
ments where masses have to be mixed and kneaded — and 
are most suitable for the preparation of viscoid masses. 
However, to adapt them entirely for this purpose, the mix- 



158 



CELLULOSE, AND CELLULOSE PRODUCTS. 



ing vessel must be so arranged that it can be tightly closed, 
SO that the viscose does not decompose during the operation, 
since decomposition should only be effected when the plastic 
mass is brought into the form the jfinished article is to have. 
Fig. 32 shows the peculiar shape of a kneading and mixing 
paddle of a kneading and mixing machine constructed by 
Werner and Pfleiderer. 

In the commencement of the operation, the entire quan- 
tity of viscose solution to be worked is brought into the 

Fig. 32. 




mixing vessel, and through a funnel placed in the lid of 
the mixing vessel the powder is allowed to run in in a thin 
jet, while the mixing paddle revolves with moderate ve- 
locity. When, in consequence of the increasing viscosity 
of the mass, its resistance to the mixing paddle becomes 
greater, the velocity of the latter is increased, and thus 
continued until a sample taken from the mixing vessel 
shows the mass to be entirely uniform. The machine is 
then stopped, the viscoid mass taken out and immediately 
moulded. 



VISCOSE AND VISCOID. 159 

The moulds used may be made of iron or brass, or of 
wood, gutta-percha, or of plaster of Paris impregnated with 
stearin. Moulds which are most frequently used should, of 
course, be made of metal, this material possessing the great- 
est power of resistance and being less subject to wear and 
tear. 

It depends on the article to be prepared whether it is to 
be moulded solid or hollow. Billiard balls, door-handles, 
buttons, ornaments in relief, etc., are moulded solid. For 
the preparation of balls, hemispherical moulds are used. 
They are pressed full of viscoid mass and, after coating two 
such hemispheres with a small quantity of thick viscose 
solution, they are joined together by vigorous pressure. In 
this manner cane-heads, door-knobs, etc., are made. 

For moulding hollow articles, plates of the thickness the 
articles are to have are first prepared from the mass. Such 
a plate is pressed into the hollow mould, the core portion 
of the mould is then laid upon it, and the mould thus put 
together is subjected to pressure in a press, by which anj 
excess of mass is forced from the mould. When the press 
is opened the core portion of the mould is first lifted off, 
and the article can then be readily detached by turning the 
mould over and giving it a gentle knock. Doll-heads are 
thus made in two halves, which are then cemented together 
with viscose solution. 

The articles when taken from the moulds being still soft 
have to be carefully laid upon a smooth board and allowed 
to remain in a place free from dust until they are solid, 
hard and dry. They are then finished by heating to about 
212° F. In case the articles should turn out lustreless, a 
beautiful lustre can be given to them by applying a coat of 
dilute (10 per cent.) viscose solution. When the articles 
are to be painted, for instance, doll-heads, the colors are 
applied to the finished article, a coating of viscose solution 
being finally put on. The colors then lie under a thin 
colorless layer of cellulose similar to a coat of a protecting 



IGO CELLULOSE, AND CELLULOSE PRODUCTS. 

glaze, and the articles may be cleansed with soap and water 
without injury to the colors. 

Viscoid masses, the filling-substances of which consist of 
cellulose or mechanical wood-pulp, acquire a hardness not 
surpassed by hard wood, and may be advantageously used 
for machine parts which otherwise have to be made by 
hand from wood. Screws and nuts may thus, for instance, 
be made from the mass while still soft, and the}'^ do not 
require finishing by hand, because coming from the same 
mould they have the same gauge. In the same manner 
shuttles, spools, small cog-wheels, etc., may be prepared by 
pressing, the cost of producing such articles being, as may 
readily be conceived, very slight as compared with those 
made by hand from wood. 

Viscoid masses filled either with cellulose, mechanical 
wood-pulp, or indiff"erent mineral powders possess in a high 
degree the power of resisting atmospheric influences, and 
sufl'er neither from rain or frost. In consequence of these 
valuable properties they are well adapted for building pur- 
poses, for the exterior as well as the interior of houses. 
Mouldings, c^^nices, lion heads and other constructive orna- 
ments may be advantageously made of this mass, which is 
cheap, and at the same time capable of great resistance, 
and it may also be used for busts, statuettes and ceramic 
articles. 



YIII. 

NITRO-CELLULOSE (GUN-COTTON, PYROXYLIN). 

When pure cellulose is brought in contact with more or 
less concentrated nitric acid, a large number of combina- 
tions is formed, the kind of combinations which are formed 
depending on the concentration of the acid, as well as on 
the time it remains in contact with the cellulose. How- 
ever, there are two distinctly marked groups of combina- 
tions, one of them being distinguished by its members 
exploding with great violence when brought in contact 
with a red-hot body, as well as by concussion and percus- 
sion, and further by being indifferent towards solvents. 
The second group, to be sure, also contains explosive bodies, 
they being, however, distinguished by the property of com- 
pletely dissolving in certain fluids. Hence we may speak 
of explosive nitro-celluloses and soluble ones, but it must 
be expressly understood that an absolutely sharp boundary 
between these two groups is not known. 

The combinations formed by the action of nitric acid 
upon cellulose were simultaneously discovered by Braconnet, 
Schcinbein, Otto and Pelouze, the explosive products for 
blasting and military purposes being first prepared by 
them. The properties of the less explosive, but readily 
soluble, combinations, as well as the numerous uses to 
which they could be applied, became accurately known 
only at a much later time. The}' are at present so num- 
erous that several large industries — manufacture of arti- 
ficial silk and of celluloid — are based upon them. 

According to former opinions regarding the formation 
and composition of the combinations belonging to these 
11 (16J) 



162 CELLULOSE, AND CELLULOSE PRODUCTS. 

groups, they were considered as nitro-compounds. In 
accordance with this assumption, by treating cellulose with 
nitric acid, the water is withdrawn from the cellulose and 
replaced by nitryl, the radical of nitric acid. However, 
when it was found that by treating cellulose for a longer or 
shorter time, as well as at different temperatures, with vary- 
ing quantities of nitric acid, combinations containing differ- 
ent quantities of nitrogen were formed, it was sought to 
explain this phenomenon by the existence of different 
kinds of nitro-cellulose, and thus hypothetical compounds 
which were to contain 1 to 11 molecules of nitryl were 
arrived at. It was further considered justifiable to assume 
that nitro-celiuloses with a certain content of nitrogen are 
insoluble, while others constitute the soluble form. How- 
ever, since nitro-celluloses can be prepared which possess 
nearly the same content of nitrogen, but one of which is in- 
soluble and the other readily soluble, these opinions can no 
longer be considered correct. 

According to modern views regarding the composition of 
gun-cotton, it cannot be designated a nitro-compound, but 
has to be termed a nitric acid ester or ether, the proof of 
the correctness of this view being found in the behavior of 
gun-cotton towards different reagents. In treating gun- 
cotton with concentrated sulphuric acid it is slowly decom- 
posed, even at the ordinary temperature, and nitric acid is 
liberated. If gun-cotton be treated with potash-lye it is, 
even if only slightly heated, completely decomposed, potas- 
sium nitrate being formed, and the cellulose with all its 
properties reappears. Even ferrous chloride acts upon 
nitro-cellulose in such a way, that the formation of ferric 
chloride is caused by the nitric acid which is liberated, and 
cellulose is again formed. 

In view of these reactions the assumption that the so- 
called nitro-cellulose is a combination formed by the re- 
placement of the hydrogen in the cellulose by the radical 
nitryl can no longer be maintained, and the view that a 



NITRO-CELLULOSE (GUN-COTTON, PYROXYLIN). 163 

series of combinations of cellulose with nitric acid — cellulose 
nitric acid esters — is in question, would seem to be correct. 
From this also results the assumption of a mono- cellulose, 
di-cellulose, tri-cellulose, up to endeca-cellulose, and the 
quantity of nitrogen found in the products depends on the 
concentration of the nitric acid used, as well as on the 
duration of the action of the acid upon the cellulose. 

Nitro-cellulose, in explosive as well as soluble form, may 
be prepared by bringing pure cellulose in contact with 
highly concentrated nitric acid, but as the latter by the 
absorption of water becomes in a short time less concen- 
trated, mixtures of nitric and sulphuric acids are generally 
used as nitrating fluids. Sulphuric acid being a body 
which fixes water with great energy, its purpose in this 
case, is to absorb the water which is formed, so that the 
concentration of the nitric acid remains the same. 

This assumption, however, does not agree with the facts 
which have been established in reference to the behavior of 
cellulose towards mixtures of very varying quantities of 
nitric and sulphuric acids. From investigations of the pro- 
ducts thus formed it would appear that the kind of combi- 
nation formed is very materially influenced by the larger 
or smaller quantity of sulphuric acid present. 

For an explanation of these facts we are indebted to the 
thorough investigations made conjointly by G. Lunge and 
E. Weintraub, and the points of practical importance for 
the preparation of nitro-cellulose will here be briefly given. 

The larger the quantity of sulphuric acid in the nitrating 
fluid in comparison with that of nitric acid, the more slowly 
the entire process is completed. By using ^ part of sul- 
phuric acid to 1 part of nitric acid, reaction is complete in 
half an hour. (It may be here remarked that the course of 
the reaction may be measured by the quantity of nitrogen 
present in the newly-formed nitro-product.) With the use 
of a mixture of 3 parts of sulphuric acid and 1 part of 
nitric acid the content of nitrogen in the product is in the 



164 CELLULOSE, AND CELLULOSE PRODUCTS. 

course of half an hour much lower than with the use of the 
previous mixture. If, finally, a fluid of 8 parts sulphuric 
acid and 1 part nitric acid be employed, reaction is not 
complete even in a month. 

With a slower course of reaction the content of nitrogen 
in the product is also changed, i. e., with an increasing 
content of sulphuric acid in the nitrating fluid, final pro- 
ducts are obtained which contain less nitrogen than with 
the use of a smaller quantity of sulphuric acid. 

The presence of a very large quantity of sulphuric acid 
(more than 8 to 1) in the nitrating fluid appears to be the 
reason why, even after remaining for so long a time in con- 
tact with the fluid, a certain quantity of the cellulose itself 
remains unchanged and is not converted into a nitro- 
compound. In our opinion, an explanation of this phe- 
nomenon may be found in the fact that, in the commence- 
ment of the operation, certain fibres of the cellulose are 
already changed by the sulphuric acid in a manner similar 
to that when cellulose is converted into vegetable parchment, 
and thus become inaccessible to the action of the nitric acid. 
That the presence of a larger quantity of sulphuric acid in 
the nitrating fluid exerts a material influence upon the 
physical structure of the product has been confirmed by the 
investigations above referred to. 

With the use of a nitrating fluid containing but a small 
quantity of sulphuric acid — about :^ to |^ of the weight of 
nitric acid — a product is obtained which possesses greater 
strength than the cellulose originally used, the fibres ap- 
pearing strongly contracted. If, on the other hand, fluids 
rich in sulphuric acid (7 to 1 upwards) are employed, the 
dry'product represents a flnely-fibered powder. 

The process of nitration is completed the more rapidly 
the higher the temperature of the fluids is, it being effected 
in the shortest time at between 140° and 176° F. In prac- 
tice it is, however, not feasible to work with such a high 
temperature, the yield of nitro-cellulose becoming con- 



NITRO-CELLULOSE (gUN-COTTON, PYROXYLIN). 165 

stahtly smaller with an increasing temperature, and a con- 
siderable portion of the substance passing into solution. 

When working with a nitrating fluid heated to 140° F., 
nitration may be considered complete in half an hour. 
The loss in cellulose was found, in this case, to amount to 
1.95 per cent. By leaving the finished product in the hot 
fluid, 5.67 per cent, of it was in the course of 4^ hours 
again destroyed. 

With the use of a fluid heated to 176° F., the destructive 
processes became still more conspicuous, and nitration, in 
this case, was generally complete in less than a quarter of 
an hour. The loss in cellulose amounted to 6.25 per cent., 
increasing in half an hour to 27.45 per cent., and in three 
hours to 52.76 per cent. 

B}?^ nitration at higher temperatures, a change in the 
structure of the nitro-cellulose takes place, it becoming 
short-fibered and brittle, and the product prepared under 
these conditions appears, after drying, as a finely-fibered 
powder. 

Towards polarized light, nitro-cellulose acts in a very 
peculiar manner, it having been asserted by some investi- 
gators that the different degrees of nitration may be recog- 
nized from the appearance ot the fibres when observed in 
polarized light. However, Lunge and Weintraub specify 
this as not being pertinent. 

In polarized light the highest degrees of nitration appear 
pale to dark blue. However, important information re- 
garding the presence of unchanged cellulose is gained by 
examining nitro-cellulose in polarized light, the unchanged 
cellulose appearing pale yellow to reddish, and lights up 
more than nitro-cellulose. It is, however, impossible to 
determine from the picture in the polarizing microscope 
the quantity of non-nitrated cellulose. If the latter 
amounts to only 5 per cent., a large portion of the field of 
vision appears already of a yellow color, and, if the content 
of cellulose increases to 10 or 15 per cent., it is no longer 



166 CELLULOSE, AND CELLULOSE PRODUCTS. 

possible to observe the polarizing phenomena of the nitro- 
cellulose, they being completely hid by those of the cellulose. 

Although the disclosures afforded by observing the fibres 
under the polarizing microscope are quite uncertain, they 
may nevertheless be utilized for gaining information in re- 
gard to the state of nitration as, for instance, is done hj 
Chardonnet, in testing the nitro-cellulose which is to be 
used for the preparation of artificial silk (see later on). 
When the field of view shows exclusively blue-appearing 
fibres, and no yellow ones can be seen, it is, at all events, a 
proof that the total quantity of cellulose used has been 
nitrated, and that the product is very likely completely 
soluble. 

In practice two main objects are especially to be attained 
in the preparation of nitro-cellulose, namely, the product 
must either be explosive to the highest degree, i. e., gun- 
cotton in the actual sense of the word, or it must dissolve 
in solvents without leaving a residue, the term collodion 
cotton being, in the latter case, generally applied to the 
product. 

In conducting the nitration of cellulose it is scarcely 
probable that a product is obtained which is in accordance 
with a positively determined combination, i. e., a nitro-cel- 
lulose of positively determined composition, the result being, 
on the contrary, always mixtures of various degrees of ni- 
tration with more or less changed cellulose. 

For practical purposes two products of diff'erent proper- 
ties come chiefly into question, namely, on the one hand, 
the preparation of a nitro-cellulose which, in exploding, 
produces the greatest dynamic effect and is suitable for the 
manufacture of blasting gelatine, and on the other, the pro- 
duction of a nitro-cellulose which can be completely dis- 
solved. The latter product has attained great importance 
for photographic use, and the manufacture of artificial silk. 

Information regarding the composition of nitro-cellulose 
produced by a certain process is sought to be obtained by 



NITRO-CELLULOSE (GUN-COTTON, PYROXYLIN). 167 

establishing the quantities of nitrogen contained in them. 
While the French chemists calculate the nitrogen in the 
form of nitric oxide which can be obtained from 1 gramme 
substance (reduced to 0° and 760 millimeters height of bar- 
ometer), the English and German chemists give the content 
of nitrogen directly in per cent. 

Conjointly with J. Bebie, G. Lunge has recently occupied 
himself with the composition and properties of the various 
nitro-celluloses, and in the commencement of a very full 
article published in the " Zeitschrift fiir angewandte 
Chemie," 1901, these investigators give the relation between 
the modes of determination adopted by the French and 
German chemists, as shown in the table below, which af- 
fords a ready comparison between the two methods of ex- 
amination. 









Ccm. nitric 


Per cent. 


Name. 




Formula. 


oxide (NO) 
in Ig. 


nitrogen (N) 
in 1 g. 


Dodeca- 




C^.H^sOglNOa)!^ 


226.17 


14.14 


Endeca- 




C2,H,A(N03)ii 


215.17 


13.47 


Deca- 


S 


C2,H3„Oio(N03),o 


203.35 


12.75 


Ennea- 


' = 


C24H3iO„(N03)9 


190.75 


11.96 


Octo- 


[ 13 


C2,H320i2(N03)8 


177.19 


11.11 


Hepta- 




C,,H330,3(N03), 


162.36 


10.18 


Hexa- 




C,,H3,Oh(N03)6 


145.93 


9.15 


Penta- 


a 


C2,H350i5(N03)5 


127.91 


8.62 


Tetra- J 




c,,K,,o,,(m,), 


107.81 


6.76 



According to the investigations of the above-mentioned 
scientists, the degrees of nitration from tetra-nitro-cellulose 
to deca-nitro-cellulose can only be obtained by treating cot- 
ton with nitric acid, while for still higher degrees of nitra- 
tion, mixtures of nitric and sulphuric acids have to be 
employed. Since in the preparation of nitro-cellulose on a 
large scale, mixtures of nitric and sulphuric acids are always 
used, such mixtures were almost exclusively employed in 
the above investigations. 



168 



CELLULOSE, AND CELLULOSE PRODUCTS. 



The influence exerted by the content of water in the acid 
mixture upon the process of nitration is shown by the table 
below : 



bb 


c 


o 




Nitrating mixtures. 


I— ( 




^ ja 










g 


^ 




ns 
















O 

a 

o 


-ij 


-b'^^^ 


% 










Solubili 
ether 
(3:1 


>^ 


Sulphuric 

acid 

SO4H2, 


Nitric 

acid 

HNO3. 


Water 


217.73 


13.65 


1.50 


177.5 


45.31 


49.07 


5.62 


210.68 


13.21 


5.40 


176.2 


42.61 


46.01 


11.38 


203.49 


12.76 


22.00 


— 


41.03 


44.45 


14.52 


200.58 


12.58 


60.00 


167.0 


40.68 


43.85 


15.49 


196.35 


12.31 


99.14 


159.0 


40.14 


43.25 


16.61 


192.15 


12.05 


99.84 


153.0 


39.45 


42.73 


17.82 


184.78 


11.59 


100.02 


156.5 


38.95 


42.15 


18.90 


174.29 


10.93 


99.82 


144.2 


38.43 


41.31 


20.26 


155.73 


9.76 


74.22 


146.0 


37.20 


40.30 


22.50 


148.51 


9.31 


1.15 


138.9 t 


36.72 


39.78 


23.50 


133.94 


8.40 


0.61 


131.2 


35.87 


38.83 


25.30 


103.69 


6.50 


1.73 


— 


34.41 


31.17 


28.42 



The considerable differences appearing in the degrees of 
nitration between the soluble and insoluble parts might be 
explained by the dilution of the nitrating mixtures which 
occurs in the course of reaction, this dilution being due to 
the withdrawal of nitric acid and to the water formed by the 
process itself. It having, however, been established by the 
investigations that a difference of a few per cent, of water 
suffices to produce degrees of nitration which differ consid- 
erably one from the other, it follows that a uniform product 
is never obtained, but always a mixture of different degrees 
of nitration. To prevent this as much as possible in prac- 
tice, the operation should be so conducted that the quantity 
of nitrating fluid is very large in proportion to cotton, the 
effect of dilution being then less pronounced. 

If the nitrating mixture contains 16.6 per cent, of water 
a completely soluble product belonging to the group of 
actual collodion cottons is obtained. From 18 per cent. 



NITRO-CELLULOSE (gUN-COTTON, PYROXYLIN). 169 

up, the content of nitrogen decreases very rapidly with the 
increase in the content of water. 

The entire group of soluble nitro-celluloses between 170 
and 196 cubic cm. is defined by a content of water which 
only amounts to 4 per cent. (16.5 to 20.5 per cent.). 
Between 7 and 8 lies the octo-nitro-cellulose with a content of 
177.2 cubic cm. of nitrogen which may be designated as the 
typical soluble nitro-cellulose — the actual collodion cotton. This 
product is always obtained by working with a nitrating mixture 
which contains 19.4-2 per cent, of water. 

This statement is of great importance for the practice, it 
pointing out the way in which the material required for 
the production of collodion for photographic purposes, as 
well as for the manufacture of artificial silk, can be pre- 
pared. According to statements made in this direction re- 
garding the manufacture of artificial silk according to 
Chardonnet, a nitrating fluid composed of 85 parts of sul- 
phuric acid and 15 parts of fuming nitric acid, is for 4 to 6 
hours allowed to act upon cotton. However, several chem- 
ists in working according to this direction obtained no 
adequate results, and even with the use of a higher temper- 
ature, the results were not more favorable, as shown in the 
following table : 



Temperature. 


Duration of 
nitration. 


Ccm. NO in 
1 gramme. 


Solubility. 


Yield. 


86° F. 
104° F. 


4 hours. 
7 hours. 


199.89 
209.90 


17.14 
15.54 


160.2 
143.1 



The solubility of the products which were last obtained 
is only slight, nitration, however, being complete, and in 
polarized light all the fibres appear of a slightly steel-blue 
color. However, it may in this case be remarked that with 
nitro-cellulose with a content of nitrogen below 190 cubic 
cm., blue lighting up could never be observed. 

The solubility of nitro-celluloses with a content below 



170 



CELLULOSE, AND CELLULOSE PRODUCTS. 



160 cubic cm. decreases, the degrees of nitration from hexa- 
nitro-cellulose downward being insoluble in ether-alcohol. 
According to Eders' investigations, which chiefly referred to 
the preparation of collodion-cottons, di-nitro-cellulose and 
tri-nitro-cellulose are soluble combinations. (See soluble 
gun-cotton or collodion-cotton later on). 

With a still greater increase in the content of water, the 
nitrating effect decreases very much, and the entire process 
seems to be turned in another direction, products possess- 
ing the properties of oxy-cellulose being now formed. They 
are soluble in dilute alkalies and can be again separated 
from these solutions by acids or alcohol. When brought 
in contact with basic coloring matters, they acquire an in- 
tense coloration, reduce Fehling's solution, and yield com- 
binations of phenyl-hydrazine. 

The effect of higher temperatures such as are used in the 
preparation of collodion cottons is shown by the summary, 
given below, of a few experiments made in this respect with 
the use of a nitrating fluid which contained 18.9 per cent, 
of water. 



Duration of 
nitration. 


Temperature 
Degrees F. 


Ccm. NO 
in 1 g. 


Solubility in 
ether-alcohol. 


Yield. 


4 hours. 
24 hours. 
4 hours. 
4 hours, 
i hour. 


62.6 
62.6 

104 

140 

140 


183.54 
184.78 
183.40 
172.48 
182.80 


95.60 
99.81 
99.58 
99.82 
99.71 


155.1 
156.2 
148.1 
52.0 
146.7 



As shown by these figures, nitration was complete in 4 
hours at the ordinary temperature and the yield was greater 
than at 104° F., but the product dissolved with greater dif- 
ficulty and less completely in the mixture of ether and 
alcohol. By increasing the temperature to 140° F., partial 
denitration took place rapidly. After 4 hours the content 
of nitrogen had dropped to 172.48 cubic cm. By allowing 



NITRO-CELLULOSE (GUN-COTTON, PYROXYLIN). 171 

the acid to act, at such a high temperature, only for a short 
time, for instance, ^ hour, nitration is complete, but if this 
time be exceeded, a decrease in the content of nitrogen im- 
mediately takes place. 

Simultaneously with denitration, the structure of the cot- 
ton is also completely destroyed ; it crumbles to a delicate 
paste, a pulverulent mass remaining behind after drying. 
The structure of the nitrated cotton is also affected by the 
content of water in the nitrating fluid. Up to a content of 
water of 15 per cent., scarcely any change in the structure 
is observed, but from 18 per cent, up, the fibres are some- 
what contracted and the peculiar twist characteristic of 
cotton disappears. With a still larger content of water the 
structure of the fibres is almost completely destroyed ; the 
cavity is torn open, and the fibres crumble to small frag- 
ments which felt together in knotty masses. The destructive 
effect is greatest when the content of water reaches 23 to 
25 per cent. 

Although all the nitro-celluloses up to the deca-combina- 
tion can be produced with the use of nitric acid alone, a 
mixture of nitric and sulphuric acids is generally used for 
the preparation of collodion cotton, a saving of nitric acid 
being thereby effected and the time of reaction shortened. 
With the use of a mixture of 1 nitric acid to 3 sulphuric 
acid the following figures were obtained : 



1 

a 


Ccm.NO. in 


Per cent. N. 


Solubility 
in ether- 
alcohol. 


Yield. 


Proportion 

of cellulose 

to nitric 

acid. 












1 


210.69 


13.21 


3.20 


174 




2 


198.10 


12.42 


98.70 


160 


1 :30 


3 


186.00 


11.72 


99.28 


157 




4 


174.81 


10.96 


99.50 


148 




5 


187.30 


11.74 


99.98 


159 


1 :12 


6 


173.83 


10.90 


99.20 


149 





172 



CELLULOSE, AND CELLULOSE PRODUCTS. 



The nitrating fluids used in these experiments were com- 
posed as follows : 



Experiment. 


1 


2 


3 


4 


5 

59.77 
20.94 
19.29 


6 


H,S04 .... 
HNO, .... 
H^O 


62.18 
21.91 
15.91 


61.53 
20.02 
18.45 


60;30 
19.71 
19.99 


38.88 
19.60 
21.52 


58.34 
20.62 
21.04 



The product obtained by experiment No. 2 closely re- 
sembles, as regards its content of nitrogen, as well as its 
solubility, the preparation to which the term pyro-collodion 
has been applied by Mendelejeff. 

The final results of further experiments made with the 
use of nitric and sulphuric acids in the proportions of 1 : 4 
and 1 : 5 are given in the table below : 



. 












fe 


Ccm.NO in 






Proportion 


Proportion 


a 


Per cent, N. 


Yield. 


of HNO3 to 


of cellulose 




Ig- 






H2SO4. 


to HNOs. 














1 


192.65 


12.08 


163 






2 


179.10 


11.23 


153 


1 :3.8 


1:30 


3 


187.58 


11.76 


156 






4 


175.23 


10.99 


151 




1:12 


5 


198.32 


12.42 


167 






6 


185.89 


11.66 


158 




1:30 


7 


168.00 


10.53 


140 


1 :5 


1:8 


8 


149.12 


9.35 









The composition of the nitrating fluids used in these 
experiments was as follows : 



Experiment. 



HNO3 
H,0. 



1 and 3 


2 and 4 


5 


6 


7 

64.85 
14.90 
20.25 


63.84 
16.96 
18.20 


62.52 
16.46 
21.02 


67.60 
13.66 
18.74 


66.37 
13.04 
20.59 



64.11 
13.62 

22.27 



NITRO-CELLULOSE (gUN-COTTON, PYROXYLIN). 173 

The temperature used in all the experiments was the 
ordinary one of a room, and the duration of nitration 24 
hours. 

With the use of nitrating fluids, the acid proportions of 
which were 1 : 3, 1 : 3.8, and 1 : 5, a few experiments were 
made at a higher temperature, and at 95° F., after allowing 
the acid mixture to act for only two hours, the same pro- 
ducts as under the above-mentioned conditions were ob- 
tained. 

When carrying on nitration according to a determined 
rule, attention has to be chiefly directed to the content of 
water in the nitrating fluid, the quality of the products 
obtained being less affected by the larger or smaller quan- 
tity of sulphuric acid. A special series of experiments, in 
which the proportion between nitric acid and water was 
strictly maintained, while the quantity of sulphuric acid 
was changed, showed that the products obtained with dilute 
mixtures have to be considered as nitro-oxycelluloses, 
or as mixtures of nitro-celluloses with nitro-oxycelluloses. 
Further experiments showed : 



0cm. NO in 


Per cent. N. 


Yield. 


Nitrating fluid. 


Ig- 


H2SO4. 


HNO3. 


H2O. 


217.26 
219.28 
220.66 
219.34 
218.73 


13.62 
13.75 
13.83 
13.75 
13.71 


173 
174 
175 
175 
175 


60.00 
62.10 
62.95 
63.72 
64.56 


27.43 
25.79 
24.95 
25.31 
24.65 


12.57 
12.11 
12.10 
10.97 
10.79 



Thus, products were obtained which, as regards their 
content of nitrogen (up to 13.83 per cent.), more closely 
approach hexa-nitro-cellulose (14.14 per cent.) than all 
previous ones produced with nitric and sulphuric acids. 
The feature of this experiment of value in practice is the 
fact, that nitro-celluloses with a high content of nitrogen 



174 CELLULOSE, AND CELLULOSE PRODUCTS. 

may be obtained with acid mixtures quite rich in water. 
By a series of special experiments it was shown that a con- 
tent within very wide limits of hyponitric acid in the nitric 
acid exerts no influence whatever upon the course of the 
process. 

The valuable investigations of G. Lunge and J. Bebie 
conclude with giving analyses of various nitro-celluloses. 
Samples of collodion cotton were first examined. One of 
them marked A, came from a Belgian factory, and is used 
for the preparation of blasting gelatine, while the other, 
marked B, from a factory at Breitenbach near Ziirich, is 
manufactured for the purpose of preparing artificial silk. 

Sample A showed in 1 g. 196.7 Cc.NO = 12.33 per cent. 
N, a solubility in ether-alcohol of 95.49 per cent., and an 
exploding point of 389.3° F., after heating during 4' 46". 

Sample B showed an exploding point of 386.6° F. after 
heating during 4' 46". The most highly nitrated actual 
gun-cotton from the Eidgenoessischen Munitionsfabrik at 
Thun proved, in regard to its explosibility, almost identical 
with the less highly nitrated collodion cotton. In other 
samples, collodion cotton also showed a somewhat higher 
exploding point than well-washed gun-cotton, while prepar- 
ations not thoroughly washed exploded at much lower de- 
grees of heat. 

PREPARATION OP GUN-COTTON. 

The first requisite for the production of gun-cotton which 
will in every respect come up to the demands made on it, 
is the presence of entirely pure cellulose, either purified cot- 
ton being used, or more rarely a fine quality of paper con- 
taining only cellulose. However, the cost of production 
being, in the latter case, much higher than with cotton, the 
latter is always used for manufacturing on a large scale. 

Raw cotton contains always certain quantities of fat, wax- 
like substances, and coloring matter. To free it from these 
bodies, it is first boiled with weak soda lye in large wooden 



NITRO-CELLULOSE (GUN-COTTON, PYROXYLIN). 175 

vats with the use of steam, then freed from lye by means of 
a centrifugal, and finally washed with water until all alka- 
line reaction has disappeared. It is then bleached with 
chlorine, washed in acidulated water, then in pure water, 
and is finally freed from water in a centrifugal, and dried. 
The dry cotton is stored, carefully protected from dust, till 
it is to be treated with nitric acid. Loose, as well as spun, 
cotton may be subjected to nitration, but many manufactur- 
ers prefer to use loosely-spun cotton, the hanks being more 
readily handled than the loose, bulky material. 

ACID USED FOR NITRATION. 

The conversion of cellulose into gun-cotton may be ef- 
fected by treating it with concentrated nitric acid alone. 
However, this process is not expedient, since by the absorp- 
tion of water the nitric acid soon becomes diluted to such an 
extent that it has to be replaced by fresh acid. At present 
mixtures of concentrated nitric and sulphuric acids are gen- 
erally used, the latter acid acting as a water-attracting body, 
and the concentration of the nitric acid is thus for a longer 
time maintained at the required degree. Nitration was 
formerly also effected by introducing thoroughly-dried and 
finely-pulverized saltpetre into concentrated sulphuric acid, 
a highly concentrated nitric acid being thus obtained. How- 
ever, many obstacles being met in completely removing the 
potassium sulphate, which dissolves with some difficulty, 
from the gun-cotton by washing, this process has been en- 
tirely abandoned, and at present mixtures of the two acids 
are only used. 

For the manufacture of very explosive products, nitric 
acid as concentrated as possible (specific gravity 1.500) 
should be used, but for readily soluble products, nitric acid 
of specific gravity 1.400, and containing in round numbers 
65 per cent, of nitric mono-hydrate, suffices. The nitric 
acid must be entirely free from foreign bodies, and contain 
but a small quantity of hyponitric acid, the product stand- 
ing next to it. 



176 CELLULOSE, AND CELLULOSE PKODUCTS. 

The sulphuric acid to be used is the highly concentrated 
white acid of commerce. It should be free from iron, and 
contain but a very small quantity (not more than 0.1 per 
cent.) of arsenic. 

Because of their properties, the storage of the acids is 
<5onnected with some difficulties. The nitric acid should 
be kept in the carboys in which it is shipped from the fac- 
tory until it is to be mixed with the sulphuric acid. The 
store-room in which the carboys are kept should be fire- 
proof, so that in case one of them bursts, and the straw in 
the basket used for packing ignites, the flames cannot 
spread. The carboys should be placed so that a bursted 
carboy can be drawn by means of a hook into the centre of 
the store-room, and the floor of the latter so planned that 
the acid can run off into a pit. Only after the burning 
basket has been entirely consumed, and the room has been 
thoroughly aired, can the latter be again entered. Pure 
-aluminium being indifferent towards concentrated nitric 
^cid, boiler-like, closed vessels of this material might be 
used for storing it. 

Sulphuric acid of fixed concentration (not below 1.600 
specific gravity), as otherwise hydrogen-gas would be 
evolved, may be kept in iron vessels, old steam boilers 
being frequently used for this purpose. Iron being brought 
into a passive state by concentrated nitric acid, nitration 
may be eff'ected in cast-iron vessels furnished with a con- 
trivance by means of which a large portion of the absorbed 
fluid may be withdrawn when the cotton has been suffi- 
ciently treated. 

When working on a very large scale, stoneware vessels 
standing in a large trough filled with water to prevent 
strong heating, are preferably used. For introducing and 
lifting out the cotton a strong glass-rod bent into a hook on 
•one end is employed. 

The nitrating fluid is the mixture of nitric and sulphuric 
-acids, in which the cotton to be nitrated is immersed. It 



NITRO-CELLULOSE (gUN-COTTON, PYROXYLIN). 1 77 

depends on the proportions in which the two acids are 
mixed, whether a very explosive, but only slightly soluble, 
mass — gun-cotton in the actual sense of the word — is ob- 
tained, or a product only slightly explosive, but readily 
soluble, to which the term collodion-cotton may be applied. 
The proportions for both these products, as determined by 
numerous experiments in practice, are as follows : 

For explosive gun-cotton : 1 part nitric acid and 3 parts 
sulphuric acid. 

For soluble gun-cotton : Equal parts of nitric acid with 75 
per cent, of nitric anhydride and concentrated sulphuric 
acid with 96 per cent, sulphuric anhydride. 

CONDITION OF THE NITRATING FLUID. 

The constancy of the composition of the acid mixture is 
of great importance for the production of a uniform pro- 
duct, whether explosive or soluble. However, in reality, 
it is quite a difficult matter to maintain this state of the 
acid mixture, because during nitration water is always 
formed, causing a dilution of the acid. Theoretically, a 
■certain quantity of acid could be used at one time, but as 
this is impossible in practice, an effort has to be made to 
maintain as long as possible the concentration of the acid 
within certain limits. It would, therefore, seem advisable 
to use nitrating vessels of comparatively large size, the ad- 
vantage gained thereby being that the concentration of the 
a,cids is not to any considerable extent reduced by successive 
nitrations. By successive immersions of fresh quantities of 
cotton in the nitrating vessel, the level of the fluid will fall, 
but if it be restored to its original height, by a workman 
allowing fresh acid mixture kept in readiness to run in, the 
dilution of the acid in the nitrating vessel is decreased by 
this addition of concentrated acids. 

In this manner the operation may for a long time be 
continued without the necessity of removing the acid mix- 
ture on account of its containing too much water. How- 
12 



178 CELLULOSE, AND CELLULOSE PRODUCTS. 

ever, as a rule, the acid has to be earlier removed for another 
reason. Many fine fibres of gun-cotton collect gradually in 
the fluid in the nitrating vessel, and when immersing fresh 
cotton, adhere so firmly to the latter as to greatly retard 
the penetration of the nitrating fluid. This may to some 
extent be remedied b}^ taking the acid from the nitrating 
vessel and filtering it through glass-wool in a stoneware 
filter, or by bringing it into a tall reservoir and allowing it 
to stand quietly until the delicate fibres have deposited on 
the bottom and the supernatant acid is clear. 

The nitrating fluids, which have been removed from the 
nitrating vessels, are always regenerated to be again util- 
ized. In doing this it is absolutely necessary to determine 
by accurate analysis the quantities of nitric and sulphuric 
acids, as well as of water, contained in the fluids. Based 
upon this analysis, it can then be calculated how much of 
the most highly concentrated acids has to be added to re- 
store the proportion between the acids as required for 
nitration. 

Since by constant regeneration an excessive quantity of 
exhausted acid would in time be obtained, fuming sulphuric 
acid is frequently used in place of ordinary sulphuric acid, 
and when sulphur trioxide can be obtained in commerce at 
suitable prices, its use for the regeneration of the acid mix- 
ture may be recommended. As regards the nitric acid to 
be employed, it need scarcely be mentioned that it should 
be as highly concentrated as possible. 

EXECUTION OF NITRATION. 

Nitration of the cotton may, as previously mentioned, be 
eflfected in stoneware vessels as well as in a cast-iron appa- 
ratus. In any case the vessels must be placed in a room 
provided with contrivances for carrying off' the gases evolved 
during nitration, they having a deleterious effect upon the 
respiratory organs of the workmen. Hence a ventilating 
hood connecting above with a pipe is placed over each 



NITRO-CELLULOSE (gUN-COTTON, PYEOXYLIN). 179 

nitrating vessel. These pipes terminate in a joint pipe, 
into which air is constantly sucked by a ventilating con- 
trivance. In smaller plants this air is forced through a 
layer of red-hot coal, the products of decomposition of the 
nitric acid being thus rendered innocuous for the neighbor- 
hood. In larger factories it is more economical to conduct 
the air loaded with products of decomposition of the nitric 
acid into a condensing tower and utilize it again for nitric 
acid. 

Fig. 33 represents an iron nitrating apparatus so arranged 

Fig. 33. 




that the gun-cotton nitrated in it can at the same time be 
quite vigorously pressed out. The cast-iron trough K, ob- 
liquely cut off on the side turned towards the workmen, is 
surrounded by a vessel T, through which water runs con- 
stantly, passing in at and passing out at 0^. The object 
of this arrangement is to carry on the operation always at 
the same temperature, and therefore hot or cold water is, 
according to the season of the year, conducted through T. 



■ 180 CELLULOSE, AND CELLULOSE PRODUCTS. 

The contrivance for pressing out the nitrated cotton con- 
sists of a grate-like iron plate R, upon which can be placed 
a solid iron plate P, which is provided with a vertical part 
Cj serving as the fulcrum of a lever. When the cotton 
just lifted out from the acid mixture is spread out upon the 
grate-like plate by placing the solid plate upon it, it can 
be vigorously pressed by means of the lever, the acid 
pressed out running back into the vessel K. 

The plate P is connected with the vertical part C. To 
the latter is secured a chain which runs over a pulley and 
carries on the upper part the weight G. By this weight the 
plate P is raised to the pivot z z, so that the cotton lifted 
out from the nitrating vessel can be placed upon the grate- 
like plate R, and pressed by placing in position the lever 
which revolves around C'^ the cotton being thus compressed 
and the fluid pressed out falls back into K. The com- 
pressed cotton is pushed through the opening and falls 
into the vessel N, where it remains until a sufficiently large 
quantity for further manipulation has accumulated. The 
pipe S serves for the introduction of fresh quantities of acid, 
the latter being allowed to run in whenever the level of the 
fluid falls below a mark on the wall of the vessel K. 

For the complete protection of the workmen from the 
vapors evolved by the nitrating fluid, the entire apparatus 
is enclosed in a case of glass and iron, the two sliding win- 
dows P and P being opened only' when cotton is to be in- 
troduced, or taken out. The gases escape through the pipe 
L, passing into a chimney in which a gas flame is constantly 
burning so that the escaping products of decomposition of 
the nitric acid are completely burnt and cannot inconveni- 
ence the neighborhood. To preserve the iron parts of the 
case from destruction by the vapors, they are repeatedly 
painted with hot coal tar, care being taken to allow one coat 
to become thoroughly dry before applying the next one. If 
the coats are carefully applied and by retouching places 
which in the course of time show rust spots, the iron is per- 
fectly protected. 



NITRO-CELLULOSE (gUN-COTTON, PYROXYLIN). 181 

In carrying on the operation of nitration, the nitrating 
vessel is first filled with the appropriate quantity of acid 
mixture which should be of the same temperature as that 
usually prevailing in the factory. The cotton, which 
should be perfectly dry, is then immersed in the fluid and 
pressed down to accelerate the escape of air. 

The proportion between acid and cotton by weight may 
vary very much, but the nitrating vessel must contain a 
sufficient quantity of fluid to allow of the cotton being rap- 
idly submerged so that it can quickly absorb the fluid. 

But a very short time is actually required for nitration, a 
piece of fine tissue-paper, for instance, becoming completely 
nitrated by immersing it for a few seconds only, in a mix- 
ture of nitric and sulphuric acids, and then rapidly washing 
it. It being, however, impossible uniformly to moisten in 
a short time a larger quantity of cotton, and no disadvan- 
tage being connected with the finished gun-cotton remain- 
ing somewhat longer in the acid mixture, no general rule 
regarding the time the cotton is to stay in the fluid can be 
given, every factory fixing this point for itself. When the 
cotton has remained for the prescribed time in the nitrating 
vessel, it is taken out, pressed, or allowed to drain off", and 
is then thrown into a vessel for the so-called after-nitration, 
which is, however, a misnomer, there being no after-effect 
of the nitrating fluid. It can only be supposed that the 
acid still remaining in the pores of the gun-cotton acts upon 
the portions of cellulose which have escaped its effects while 
in the nitrating fluid, and converts them also into gun- 
cotton. 

In place of employing the kind of vessels above described, 
nitration may also be eff'ected in a centrifugal apparatus 
and the nitrated cotton dried by centrifugal force. The 
nitrating drum in this apparatus is usuall}'^ constructed of 
wrought iron or steel, but these materials being subject to 
quite rapid wear, drums of aluminium have recentl}^ been 
introduced in some factories, it being claimed that this 



182 CELLULOSE, AND CELLULOSE PRODUCTS. 

metal is capable of offering great resistance to the nitrating 
fluid. 

The perforated drum of the centrifugal is enclosed in a 
cast-iron jacket, and is impelled from below. During the 
operation it is closed, the vapors evolved being carried off 
by a pipe in the lid. The centrifugal is filled four-fifths 
full with acid mixture and, while slowly revolving the cot- 
ton is rapidly introduced, and the acid is for about thirty 
minutes allowed to act upon it. The acid is then allowed 
to run off, and the centrifugal is made to revolve very rap- 
idly so that the fluid adhering to the gun-cotton is whirled 
out, this operation being finished in a short time. The 
drum is then quickly stopped by means of a brake, and the 
gun-cotton, which now feels almost dry, is lifted out. The 
drum can then be immediately used for another operation. 

With the use of a nitrating centrifugal, so-called after- 
nitration is entirely dispensed with, and care must be taken 
that by the employment of a larger quantity of nitrating 
fluid, conversion of the cellulose into nitro-cellulose is com- 
pleted in the centrifugal, this being attained by taking a 
comparatively very large quantity of the acid mixture for 
a fixed weight of cotton. In some factories a quantity of 
acid mixture amounting to two hundred times the weight 
of cotton is used. 

Although nitration is rapidly effected in the centrifugal 
apparatus, its use is not free from danger, it having been 
observed that the cotton frequently ignites, this taking 
place generally towards the end of whirling out. This 
phenomenon may be explained by the rise in temperature 
in the cotton when pressed with great force against the 
circumference of the drum by the rapid revolution of the 
centrifugal. 

When working with the ordinary apparatus, and then 
leaving the gun-cotton to after-nitration, the operation in 
the various factories takes from three to twenty-four hours. 
It is advisable to furnish the vessels used for after-nitration 



NITRO-CELLULOSE (gUN-COTTON, PYROXYLIN). 188 

with perforated bottoms through which the acid draining 
off from the mass can run off. 

WASHING THE GUN-COTTON. 

In the further manipulation of the gun-cotton, the fluid 
contained in its interior has to be removed, and replaced 
by pure water. Although this operation has the appear- 
ance of being very simple, it nevertheless requires close 
attention, since on the complete removal of the fluid depends 
not only the stability of the product, but also security in 
handling and storing it. It happens sometimes that in 
washing gun-cotton it ignites when introduced into the 
washing tank, and to reduce this danger to a minimum, 
the rooms in which nitration and after-nitration are effected 
should be entirely separated from the wash-room. The 
vessels used for after-nitration are placed alongside the par- 
tition wall through which holes have been cut. In the 
wash-room, underneath these holes, is an inclined table 
covered with lead. While one workman lifts by means of a 
pair of tongs the moist hanks from the vessels and passes 
them through one of the holes in the wall, another workman 
draws them from the table and places them immediately 
in the wash-tank. 

The wash-tank consists best of a trough divided in the 
centre by a board, which, however, should not extend to 
the ends of the trough. The wash-water flows in from the 
bottom at one end and runs off through a notch cut in the 
upper edge of the trough. By this arrangement, the water, 
together with the hanks placed in it, constantly circulates 
in the trough, all parts of the gun-cotton being thus brought 
into intimate contact with it. For the purpose of catching 
small particles of gun-cotton carried along by the water 
running off, a basket is placed underneath the notch in the 
trough. 

The gun-cotton remains in the wash-tank until, when 
rubbed with litmus-paper, the latter no longer reddens. 



184 CELLULOSE, AND CELLULOSE PRODUCTS. 

It is then completely freed from water by whirling in a 
centrifugal. 

If gun-cotton, no matter how carefully washed, be left for 
some time to itself, it undergoes changes by the acid still 
remaining in the interior of the cells exerting a decompos- 
ing effect. This acid has, therefore, to be removed, which 
is generally accomplished by boiling or steaming. Boiling 
is effected in a large vat with a false perforated bottom. 
The vat having been filled with gun-cotton and water, 
steam is introduced below the perforated bottom. In some 
factories boiling is finished in three hours, while in others 
it is continued for up to three days. 

In order to ensure the removal of the acid the water may 
be mixed with ammonium carbonate, about f to 1 oz. per 
quart of water. Steaming after boiling has been highly 
recommended for obtaining a product absolutely free from 
acid. For this purpose the water is discharged from the 
boiling vat, and steam introduced below the false bottom 
until it commences to escape in a non-condensed state from 
the top. It is claimed to have been observed that by long- 
continued boiling the content of nitrogen in the gun-cotton 
is decreased, which, of course, must be an injury to it, and 
that this is not the case in continued steaming. 

However, by all these operations the gun-cotton has not 
been freed from the last traces of acid, and this purpose can 
only be attained by thoroughly comminuting it in the pres- 
ence of a large quantity of water. For masses of the fibrous 
nature of cotton the best apparatus is that known as a beater 
or hollander used in paper mills for working pulp. It con- 
sists of an oblong tank closed on both ends by semi-circular 
pieces. It is divided by a short, vertical partition into two 
parts. The floor of one part is sloped and. a box of knives 
is fixed into it. Over this box of knives revolves a cylinder 
also furnished with knives, and its distance from the lower 
knives can be regulated at will. By the revolution of the 
cylinder the water, with which the apparatus is filled, is 



NITRO-CELLULOSE (GUN-COTTON, PYROXYLIn). 185 

constantly kept in a circling motion and the hanks of gun- 
cotton thrown into the water are drawn between the knives 
of the revolving cylinder and those fixed in the box, and 
cut up. As comminution progresses, the cutting cylinder 
is lowered until the distance between the knives has finally 
been reduced to fractions of a millimeter. 

A certain portion of the gun-cotton is for 4 to 8 hours 
treated in the hollander, or till the pulp — as the commi- 
nuted mass is called — has acquired the requisite degree of 
fineness. It is then tested by taking a sample by means of 
a ladle from the trough of the hollander, and allowing it to 
stand quietly for some time. The water is then carefully 
poured off" as long as it is quite clear. Fresh water is then 
poured upon the sample and after slightly agitating the 
vessel, the water is again allowed to run off. After this wash- 
ing operation, nothing should finally remain in the vessel ; 
if there should be a residue of plainly-perceptible, coarser 
fibres, it is proof of the manipulation of the mass not hav- 
ing been for a sufficiently long time continued. When the 
mass in the hollander has acquired the proper degree of 
fineness, it is discharged either by opening a valve in the 
bottom of the trough, or by sucking off with a pump. The 
separation of the comminuted gun-cotton from the water is 
generally effected by means of a centrifugal, the basket of 
which consists of closely-woven wire lined inside with linen 
cloths. Some fine particles of gun-cotton being neverthe- 
less carried along with the water, the latter is first allowed 
to run into a larger vessel, in which the particles of gun- 
cotton gradually settle on the bottom. The supernatant 
water is then carefully drawn off. 

By treatment in the centrifugal the content of water in 
the gun-cotton is reduced to about 30 per cent. It is 
brought into lead-lined wooden boxes and covered with a 
linen cloth, which keeps out the dust, but does not prevent 
the mass from drying slowly. 

Up to the time the gun-cotton is brought into the store- 



186 CELLULOSE, AND CELLULOSE PRODUCTS. 

boxes the operations are the same, no matter whether an 
explosive product — actual gun-cotton — or a readily soluble 
product — collodion-cotton — is to be prepared. For both 
purposes, cotton perfectly free from water must be used. 

DRYING THE GUN-COTTON. 

Although gun-cotton can be heated to between 140° and 
158° F. without igniting, no factory would dare to run the 
risk of drying larger quantities of it at such a high tem- 
perature, since its explosion might have frightful conse- 
quences. Drying even at temperatures below 122° F. is 
dangerous, dry gun-cotton being a body which becomes 
highly electric by slight friction, and by a stronger current 
of air passing over it enough electricity might be generated 
for a spark to leap over and ignite the entire mass. It is, 
therefore, necessary to use special precautions in drying 
gun-cotton. 

Drying upon frames covered with linen upon which the 
gun-cotton is spread out in thin layers, has the appearance 
of being a very simple process, but, according to Guttmann, 
it is objectionable, because the gun-cotton is thereby com- 
pletely insulated, and there is danger of an electric discharge, 
especially if drying is effected at a higher temperature. 

To be entirely secure from an electric tension, Guttmann 
uses for drying, copper-plates provided with conical open- 
ings with a diameter of I millimeter on top and of 1 milli- 
meter on the bottom, thus rendering it impossible for them 
to be stopped-up by the gun-cotton. The copper plates are 
covered on the edges with leather to prevent friction, and 
are placed one above the other in the drying room. They 
are connected one with the other by metallic strips, these 
conductors being continued into the ground. This arrange- 
ment renders an accumulation of electricity in the gun- 
cotton impossible, any electricity developed being directly 
conducted into the ground. 

Heating the drying room is effected by air being con- 



NITRO-CELLULOSE (gUN-COTTON, PYROXYLIN). 187 

stantly conducted by a ventilator over a system of rib- 
heating enclosed in a box. The air thus heated passes 
beneath the drying plates, which are enclosed in boxes, and 
leaves them heavily loaded with moisture. To prevent 
heating above a fixed temperature, the drying boxes are 
furnished with electric thermometers which indicate by ring- 
ing a bell when the maximum temperature — which should 
not be above 104° F. — is exceeded. 

Perfectly dry gun-cotton — and this applies also to col- 
lodion-cotton — is an exceedingly hygroscopic body, and 
very rapidly absorbs moisture from the air. It must, 
therefore, when taken from the drying boxes, be immedi- 
ately packed in air-tight vessels, bags of rubber or of fabrics 
impregnated with rubber being used for the purpose. Well- 
made wooden boxes, the lids of which are made air-tight 
by rubber strips on the edges, may also be employed. If 
collodion-cotton has been prepared, it is advisable to dis- 
solve it immediately when it comes from the drying boxes, 
this having the additional advantage of the solutions, by 
standing for some time, becoming perfectly clear. 

EXPLOSIVE GUN-COTTON. 

The effect of highly explosive nitro-cellulose — the actual 
gun-cotton — intended for blasting purposes, will be the 
more powerful the smaller the volume into which it is com- 
pressed. It is, therefore, made into cylindrical or prismatic 
bodies of known weight, and tlie dynamic effect of such a 
block can at the outset be established. Gun-cotton can 
only be pressed while in a moist state, and even when sub- 
jected to the most powerful pressure always contains a cer- 
tain amount of water. Its explosive power is, however, not 
affected by this content of moisture, explosion being brought 
about by making, while pressing the block, a cylindrical 
opening in it in which a fuse of dry gun-cotton is inserted. 

When gun-cotton is to be compressed, it is stirred with 
luke-warm water to a thin paste, and in doing this, the pro- 



188 CELLULOSE, AND CELLULOSE PRODUCTS. 

portion of weight of gun-cotton to that of water has to be 
known. This paste is, as a rule, first freed from the larger 
portion of water by hand-presses, the shape the finished 
piece is to have being also given to it. 

The article thus preparatively pressed is subjected in 
hydraulic presses to as strong a pressure as can be pro- 
duced. The presses must be so arranged that the water 
pressed out from the mass can escape, otherwise pressure 
would be ineffective, since fluids oppose great resistance to 
compression. In the presses variously shaped bodies of 
gun-cotton are produced, the most common shapes being 
cylinders or slightly conical pieces, because they can be most 
readily removed from the moulds of bronze. For certain 
purposes, for instance, for loading torpedoes, the gun-cotton 
is compressed in the form of cylindrical segments, which, 
when put together, make up a slightly tapering cylinder. 
Smaller pieces similar to the first ones are laid one above 
the other, a body fitting accurately into the charging space 
of the torpedo being thus formed. Compressed gun-cotton 
being very hygroscopic, the compressed articles, when fin- 
ished, are immediately coated with a water-proof lacquer. 

INCREASING THE STABILITY OF THE NITRO-CELLULOSE. 

The nitro-celluloses, so far as at present known, belong to 
the constant combinations, i. e., they remain entirely un- 
changed in the air or under water, a change taking place 
only in consequence of an exterior influence. This im- 
mutability, however, belongs only to products absolutely 
free from the slightest trace of free acid, nitro-celluloses 
which contain free acid, be it never so little, being subject to 
change, though it may progress very slowly. The change 
manifests itself first by the originally pure-white mass turn- 
ing yellowish and acquiring in the course of time a quite 
dark-brown color, and after a long time, the nitro-cellulose 
is even converted into a dark-colored, smeary mass. The 
author of this work noticed, in the course of thirty years, 



NITRO-CELLULOSE (gUN-COTTON, PYROXYLIN). 189 

these phenomena in a small quantity of explosive nitro- 
cellulose prepared by himself and which was kept in a 
vessel closed with a ground-glass stopper. Strange to say, 
on opening the vessel, the mass showed no odor of nitric 
oxide, and it remained perfectly odorless until it passed into 
the smeary state. The gun-cotton above-mentioned having 
only been thoroughly washed with cold water contained 
probably small quantities of free acid. 

According to the process of A. Luck and C. F. Gross, the 
stabilit}^ of nitro-cellulose may be increased by treatment 
with metallic salts, their solutions being allowed to act 
either directly upon the nitro-cellulose, or with the co- 
operation of acetone. In the first case, the nitro-cellulose 
is for 30 to 60 minutes treated in a one per cent, solution 
of lead acetate or zinc acetate at a temperature of from 
176° to 212° F. The nitro-cellulose is then washed until 
the wash water shows no trace of the metallic salt. 

According to the other process, acetone, to which has been 
added 1 per cent, of its weight of the metallic salt, is poured 
over the nitro-cellulose, the treatment being, in this case, 
for half an hour at the ordinary temperature. The fluid is 
finally drawn off, and the nitro-cellulose thoroughly washed. 
By both these methods of treatment, a basic salt is claimed 
to be formed from the residue of acid in the nitro-cellulose 
with the metal, thus, for instance, of the lead salt up to 2 
per cent, of lead oxide being found in the form of a basic 
combination. 

According to 0. R. Schulz's process the nitro-cellulose is 
rendered very stable by bringing it, when freed from acid 
in the ordinary manner by washing, into a pressure-boiler, 
together with several times its weight of water, and heating 
to 275° F. By increasing the pressure up to 5 or 6 atmos- 
pheres the operation is in a short time finished, and the 
nitro-cellulose breaks up to a fine powder, in which form it 
is especially suitable for the manufacture of cartridges. If 
heating be effected at as low a pressure as 3 atmospheres— 



190 CELLULOSE, AND CELLULOSE PRODUCTS. 

corresponding to 275° F. — the nitro-cellulose is also ren- 
dered stable, but heating has to be continued for a longer 
time. 

The nitro-cellulose thus treated in the boiler is finally 
washed in cold water for the removal of the soluble bodies. 
With the use of this process only 2V to ^V of the quantity of 
water necessary for washing by the ordinary method is said 
to be required. 

SOLUBLE GUN-COTTON OR COLLODION-COTTON. 

In describing the preparation of nitrated cotton, atten- 
tion has been drawn to the fact that there is no fixed 
boundary between explosive and soluble gun-cotton, but 
that the latter can be obtained by a suitable change in the 
proportions of the acid mixture. Experience has shown 
that this can be best accomplished by using equal parts of 
sulphuric and nitric acids as nitrating fluid. The nitric 
acid should contain 75 per cent, of nitric anhydride, and 
the sulphuric acid 96 per cent, of sulphuric anhydride. 
The fluid is allowed to act upon the cotton for from 60 to 
90 minutes at a temperature of 104° F., and the resulting 
product is immediately washed. 

Collodion-cotton having recently become of great import- 
ance for the preparation of textile threads, to which the 
term artificial silk has been applied, greater demands are 
now made on it than formerly, when it was chiefly used 
for photographic and medicinal purposes. For these appli- 
cations it sufficed for the collodion-cotton to dissolve clear, 
and, after the evaporation of the solvent, yield a film pos- 
sessing a certain strength and elasticity. 

With reference to the use of collodion-cotton for the manu- 
facture of textile threads of very slight diameter, great value 
is at present attached to the preparation of a product yield- 
ing a solution of great viscosity, the manufacture of very 
thin threads being only possible with such a solution. 

It has been found that the duration of the action of the 



NITRO-CELLULOSE (gUN-COTTON, P\'R0XYLIN). 191 

acid mixture upon the cotton exerts great influence upon 
the viscosity of solutions of collodion-cotton. The content 
of nitrogen is also said to be of considerable importance, 
though this is disputed by many investigators. 

It may here be emphasized that collodion-cotton is never 
entirely uniform as regards its composition, and that a pro- 
duct of quite uniform general properties can only be obtained 
by always working with cotton of the same degree of fineness, 
using an acid mixture of the same composition, and con- 
ducting the operation in the same manner as regards tem- 
perature and duration of the action of the acid mixture. 
All these conditions have, therefore, to be taken into con- 
sideration in the manufacture of large quantities of collo- 
dion-cotton of uniform quality. The manufacturers who 
require collodion-cotton have determined the correct pro- 
portions suitable for their purposes by exhaustive experi- 
ments, and if they treat their processes of nitration as 
secrets, they cannot be charged with assuming an air of 
mysteriousness. 

For the production of collodion-cotton, the solutions of 
which are to possess a great degree of viscosity, a higher 
temperature should never be used for nitration, and to pre- 
vent a rise in the temperature, it is advisable to place the 
nitrating vessels in a tank filled with cold water. The pro- 
cess of nitration progres,sing more slowly at a lower tem- 
perature, the cotton is allowed to remain a somewhat longer 
time in the acid mixture. It is then pressed and imme- 
diately washed, the same care being exercised as in washing 
explosive cotton. The object of comminuting the cotton in 
the hollander is, in this case, not only to remove the acids, 
but also to obtain the product in a very finely divided state, 
it being thus more readily brought into solution. 

According to the investigations of G. Lunge and J. Bebie, 
previously referred to, the solubility of nitro-celluloses is 
intimately connected with the content of nitrogen in the 
products ; gun-cotton, which contains as much nitrogen as 



192 CELLULOSE, AND CELLULOSE PRODUCTS. 

possible, behaving differently towards various solvents. It 
dissolves in acetic ether, acetone, benzol and nitrobenzol, 
but not in nitroglycerine. It is, however, dissolved by a 
mixture of nitroglycerine and acetone, such a solution serv- 
ing for the preparation of one of the most effective blasting 
agents which is known under the name of blasting-gelatine. 

Complete solubility in a mixture of two parts of ether 
and one part of alcohol may be considered characteristic of 
properly prepared collodion-cotton, though there is a pro- 
duct which also dissolves in a mixture of ether and alcohol 
in which the proportion of the latter is much larger. 

If nitro-cellulose be treated at a moderate heat with 
alcoholic solution of caustic soda or caustic potash, the 
nitro-combination is in a very short time disintegrated, 
cellulose remaining behind. This reaction is of great 
importance for the production of threads and tissues from 
collodion solutions, as by reason of their great inflamma- 
bility they would be of no use whatever. However, when 
treated for a short time with solution of an alkali, they 
rank, as regards inflammability, with ordinary cotton tissue. 

It has from many sides been asserted that a good quality 
of collodion-cotton can only be obtained by nitrating line 
tissue-paper which consists almost entirely of pure cellulose. 
Direct experiments in this direction have proved that an 
excellent quality of collodion-cotton can actually be pre- 
pared from such paper, it being only necessary for the 
purpose of nitration, slowly to draw strips of the paper over 
glass rods placed horizontally in the nitrating vessel and 
allow them to drain off. If, however, the expense of pre- 
paring collodion-cotton from paper is compared with the 
cost of producing it from cotton, the calculation results in 
favor of cotton. It may be confidently asserted that all 
that is necessary is to free cotton from all foreign bodies, 
i. e., to convert it into pure cellulose, to be enabled to pro- 
duce from it as good a quality of collodion-cotton as from 
paper. 



NITRO-CELLULOSE (gUN-COTTON, PYROXYLIN). 193 

COLLODION. 

Nitro-cellulose, with a certain content of nitrogen, is 
capable of dissolving in a number of fluids, and it then forms 
a viscous mass possessing great adhesive power, to which 
the term collodion has been applied. When collodion is 
left to itself until the solvent evaporates, the nitro-cellulose 
remains behind in the form of a structureless film, which is 
perfectly colorless, and is distinguished by considerable 
solidity and high lustre. 

Collodion found originally only limited application in 
the healing art, it being used for the purpose of closing 
wounds air-tight to prevent the colonization of organisms 
which cause gangrenous and other complications detri- 
mental to the healing process. 

Solutions of nitro-cellulose gained in importance only 
from the time when the use of collodion in photography 
became general, and they retained this importance until 
the photographic process turned more and more towards 
the so-called dry plates, the sensitized layer of which con- 
sists of gelatine. However, collodion regained its great 
importance by reason of the invention of the preparation of 
artificial silk, large quantities of it being at present manu- 
factured for this purpose. 

In speaking later on of the manufacture of artificial silk, 
the preparation of collodion for this purpose will be referred 
to, and only the varieties which are of importance for 
photographic purposes will here be discussed. 

COLLODION FOR PHOTOGRAPHIC PURPOSES. 

It has been found by special investigations that a not 
highly nitrated nitro-cellulose is best adapted for the pre- 
paration of collodion for photographic purposes as it dis- 
solves with the greatest ease. Several authors recommend 
the finest quality of tissue-paper as raw material for its 
preparation, but the same result is without question ob- 
13 



194 - CELLULOSE, AND CELl ULOSE PEODUCTS. 

tained by using, in place of this expensive material, a fine 
quality of purified cotton. 

A series of nitro-celluloses is known, the formation of which 

depends on the action for a varying time of the nitrating 

fluid and, partially, also on its concentration. According 

to Eber the composition of these combinations is as follows 

C}:^ (tbe formula for the cellulose having been taken double): 

Content of 
nitrogen. 

1. Cellulose-hexanitrate, Cj2H,40^(N03)6 . . • . 14.14 pei* cent. 

2. Cellulcse-pentanitrate, CijH.jOslNOaJs . . . 12.75 *' 

3. Cellulose-tetra nitrate, CijHieOeCNOa)^ .... 11.11 " 

4. Cellulose-trinitrate, Ci2H,707(NOs)3 9.15 

6. Cellulose-dinitrate, C,2H,808(N03)2 6.76 " 

The cellulose hexanitrate is the insoluble explosive com- 
pound which, however, contains alwaj's small quantities of 
soluble substance. Cellulose pentanitrate is soluble in a 
mixture of alcohol and ether. It is obtained by leaving 
cotton for several hours (up to five) at the ordinary tempera- 
ture in contact with a mixture of equal parts of concen- 
trated sulphuric and nitric acids of specific gravity 1.40. 
^The resulting cellulose, as mentioned above, is soluble in a 
mixture of alcohol and ether, but if the mixture contains 
only a small quantity of ether, the cellulose pentanitrate 
alone is dissolved, the admixed tetranitrate and trinitrate 
remaining undissolved. 

Cellulose tetranitrate may be obtained by bringing 0.63 
oz, (18 grammes) of tissue paper cut up into thin strips, 
into a mixture of equal parts of sulphuric acid of specific 
gravity 1.845 and nitric acid of specific gravity 1.40, and 
allowing it to remain \ hour in the acid mixture, maintain- 
ing the temperature during this time at 176° F. The pro- 
duct obtained in this manner is identical with celloidin, an 
article furnished b}'' Scheering's factory at Berlin. Besides 
tetranitrate, trinitrate is also formed, and the separation of 
the two compounds is not readily accomplished. The tetra- 



NITRO-CELLULGSE (gUN-COTTON, PYROXYLIn). 195 

nitrate is insoluble in ether as well as in alcohol, but dis- 
solves in a mixture of them, as well as in acetic ether, 
methyl alcohol, in a mixture of acetic ether and alcohol, 
and in glacial acetic acid. 

Cellulose trinitrate dissolves slowly at the ordinary tem- 
perature in absolute alcohol ; it is readily soluble in acetic 
ether, methyl alcohol and boiling glacial acetic, acid. A 
concentrated alcoholic solution acquires a milky appear- 
ance by the addition of ether. 

Cellulose dinitrate may be obtained in various ways. 
According to one method, it is formed by allowing highly 
dilute mixtures of nitric and sulphuric acids to act at a 
higher temperature upon cellulose until an abundance of 
red vapors is evolved, and the mass commences to dissolve. 
Dinitro-cellulose may also be obtained by mixing collodion 
solution containing 2 to 4 per cent, of nitro-cellulose with a 
quantity of alcoholic potash lye about three times as large 
as would be required for the neutralization of the nitric acid 
present. After one or two hours, the fluid is diluted with 
water and neutralized with dilute sulphuric acid, a floccu- 
lent precipitate being formed, which is carefully washed 
and dried. It consists of dinitro-cellulose which ignites 
with difficulty and detonates when heated to 347° F. It is 
readily soluble in a mixture of ether and absolute alcohol, 
as well as in absolute alcohol alone, in glacial acetic acid, 
acetic ether, acetone, and methyl alcohol, but only with 
great difficulty in pure ether. 

The behavior in drying of a solution of dinitro-cellulose 
in ether-alcohol is of special importance for the preparation 
of collodion for photographic purposes. By allowing such 
a solution to evaporate upon a glass-plate, a milky-turbid, 
soft film is formed which is not transparent, but only trans- 
lucent. As only a slight admixture of this dinitro-cellulose 
suffices for collodion to exhibit this phenomenon, this com- 
pound has to be considered as entirely unsuitable for the 
preparation of a good quality of collodion. 



196 CELLULOSE, AND CELLULOSE PRODUCTS, 

For the production of collodion serviceable for photo- 
graphic purposes as well as for other applications, the 
collodion-cotton has to be perfectly neutralized. When a 
sample of the cotton is moistened with water, and after 
squeezing out the water, litmus paper is reddened by it, 
the acid adhering to the cotton has to be neutralized. For 
this purpose the cotton is for half an hour soaked in 
ammonia diluted with four times its quantity of water, 
then thoroughly washed, and completely dried upon a 
plate placed upon a pot of boiling water. 

For the preparation of the solution, 50 parts of ether and 
50 parts of 95 per cent, alcohol are used for 2 parts by 
weight of dry cotton. The alcohol is first poured over the 
cotton, and when the latter has swelled up, the ether is 
added, solution being accelerated by vigorous shaking. A 
2 per cent, collodion is in this manner obtained. 

The physical condition of collodion-cotton has a notice- 
able influence upon its solubility. Pulverulent cotton, 
which crumbles to dust when rubbed between the fingers, 
has to be dissolved in a mixture of 40 parts of alcohol and 
60 parts of ether, otherwise the resulting collodion layer 
will not turn out solid. 

Collodion solution is best kept in glass bottles of small 
diameter in a cool, dark place where it is protected from 
shocks. After standing for some time the undissolved par- 
ticles of cotton fall to the bottom, where they form a quite 
heavy deposit, the supernatant fluid being perfectly clear. 
By carefully tilting the bottles, the clear fluid may be 
almost entirely poured off". 

The preparation of collodion solution for the purpose of 
manufacturing artificial silk diff'ers in many respects from 
the process above described, and will be referred to in detail 
in speaking later on of the manufacture of artificial silk 
according to Chardonnet. 



NITRO-CELLULOSE (gUN-COTTON, PYROXYLIN). J 97 

ELASTIC MASSES FROM NITRO-CELLULOSE (ARTIFICIAL RUBBER.) 

A solution of nitro-cellulose in volatile solvents yields, 
after the evaporation of the latter, a layer of structureless 
nitro-cellulose, which, however, becomes extremely brittle 
by drying. This mass may to a certain extent be rendered 
more flexible by adding to the solution a small quantity of 
castor oil. The latter is dissolved in strong alcohol, and a 
quantity of the solution, amounting to about 2 per cent, 
of the weight of the dry nitro-cellulose, is added to the 
collodion. 

The castor oil, after the evaporation of the solvent re- 
maining, uniformly distributed throughout the nitro-cellu- 
lose, imparts to the latter a certain degree of flexibility, and 
prevents thin layers of the mass from becoming brittle, 
without, however, conferring upon them a higher degree of 
elasticity. 

For the production from nitro-cellulose of masses possess- 
ing considerable elasticity other means have to be adopted. 
The nitro-cellulose has to be dissolved in fluids having a 
high boiling point, and which consequently do not evap- 
orate in the air, but impart to the mass a soft, elastic 
property similar to that of collodion still containing rem- 
nants of the solvent. 

The following fluids possess these properties and are at 
the same time capable of dissolving nitro-cellulose : Nitro- 
benzol, nitrotoluol, dinitrotoluol, nitrocumol, nitronaph- 
thalin, etc. However, their use in practice is almost out of 
the question because they are too expensive. 

A uniform mass may, to be sure, be produced by bringing 
dry soluble nitro-cellulose in contact with one of these sol- 
vents or a mixture of them ; but long-continued manipula- 
tion is required. The object may, however, be attained in 
a more simple manner by first dissolving the nitro-cellulose 
in one of the volatile solvents ordinarily used, then adding 
one of the above-mentioned less volatile solvents, and allow- 
ing the volatile solvent to evaporate. 



198 CELLULOSE, AND CELLULOSE PRODUCTS. 

For this purpose it is not necessary to prepare an entirely 
clear solution of nitro-cellulose in a volatile solvent, only 
enough of the latter being used to cause the nitro-cellulose 
to swell up so that a mass resembling very thick glue solu- 
tion is formed. 

A kneading apparatus allowing of thorough mechanical 
manipulation is used for preparing the mass. Since dur- 
ing this manipulation, the volatile solvent would evaporate, 
the kneading apparatus should be placed in a box which 
can be closed air-tight, and provision must be made for a 
contrivance by means of which a current of warm air can 
be passed through the apparatus. 

The nitro-cellulose having been intrpduced, the apparatus 
is closed, and the necessary quantity of solvent admitted. 
The most suitable solvent is a mixture of equal parts of 
ether and alcohol, though acetone or methyl alcohol may 
also be used. The mixing contrivance is then set in 
motion and kept going until the contents of the apparatus 
have been converted into a uniform mass in which no lumps 
of swollen, undissolved nitro-cellulose are noticed. The 
heavy volatile solvent is then introduced, and the mixing 
apparatus kept constantly in motion until the mass has 
again become homogeneous. This is the period at which 
the greater part of the volatile solvent may be regained by 
distillation. 

For this purpose a current of warm air is passed through 
the apparatus, and, when loaded with the vapors of alcohol 
and ether, is conducted through a cooling pipe in which 
the vapors are condensed. However, the entire quantity of 
volatile solvent must not be distilled off, otherwise the mass 
in the apparatus would become so viscous as to clog the 
kneading contrivance. 

The further manipulation of the mass is effected by rolls, 
the rest of the volatile solvent still contained in it being 
thereby completely evaporated. Rolling has to be several 
times repeated to make the mass thoroughly homogeneous. 



NITRO-CELLULOSE (gUN-COTTON, PYROXYLIN). 199 

The nature of the masses finally obtained depends on the 
proportional quantities of nitro-cellulose and solvent. The 
more of the latter is present the more elastic the masses 
will be, and by a suitable change in the proportions, masses 
almost equal, as regards softness and elasticity, to a fine 
quality of rubber may be obtained. The smaller the quan- 
tity of solvent, the more solid and harder the resulting 
masses will be. 

These masses, when heated, acquire a higher degree of 
stablity, and can then by pressure be brought into any 
shape desired, and as they can be readily mixed with in- 
different bodies, articles of very varying appearance may 
be made of them. For mixing purposes, powders of cheap, 
indifferent bodies, such as chalk, asbestus, talcum, etc., are 
especially suitable. If other than white masses are to be 
prepared, any desired coloring matter may be mixed with 
the white powders, colored masses of very neat appearance 
being thus obtained. On account of their great elasticity, 
the term artificial rubber has been applied to these peculiar 
nitro-cellulose masses, and for many purposes they may 
serve as substitutes for rubber. 

. The above-described masses, consisting as they do largely 
of nitro-cellulose, are quite inflammable, without, however, 
exhibiting any explosive properties. The inflammability, 
however, becomes less with the use of a larger quantity of 
indifferent substances, it being thereby actually reduced to 
a very slight degree, and it may be still further decreased 
by superficially denitrating the finished articles. This is 
accomplished by dipping them for a short time in hot soda 
lye, the outer layers of nitro-cellulose being thereby con- 
verted into cellulose. An article thus treated will not 
ignite, even when brought in contact with a red-hot body, 
the point of contact being simply blackened by the carbon- 
ization of the outer cellulose layers. 

The elastic nitro-cellulose masses prepared according to 
the process above described, are by many investigators con- 



200 CELLULOSE, AND CELLULOSE PRODUCTS. 

sidered as deserving the greatest attention of all the bodies 
which have been proposed as substitutes for rubber, they 
approaching nearest, as regards their properties, the genu- 
ine article, without, however, being capable of entirely re- 
placing it. 

CELLULOSE ESTERS. 

In addition to the esters yielded by cellulose by the 
action of nitric acid, analogous combinations with other 
acids may be prepared. But a small number of combina- 
tions belonging to this series are at present known, but it 
may be supposed that many of them may in the future ac- 
quire a certain importance for the industries. It has, 
therefore, been considered advisable to give a few facts 
regarding the nature and preparation of these combinations. 

CELLULOSE ACETIC ESTER. 

Cellulose tetra-acetate or cellulose acetic ester is prepared, 
according to Henckel-Donnersmark's process, from a mole- 
cular mixture of cellulose and magnesium acetate, and, 
therefore, 630 grammes (21.87 ozs.) of magnesium acetate 
have to be used for every 720 grammes (25.39 ozs.) of 
cellulose, pure cellulose prepared from cellulose sulpho- 
carbonate being said to be especially suitable for preparing 
the combination. The above-mentioned mixture of cellu- 
lose and magnesium acetate is intimately mixed in a 
kneading machine, the mixing vessel of which can be 
heated, with 810 grammes (28.57 ozs.) of acetyl chloride 
and 450 grammes (15.87 ozs.) of anhydrous acetic acid. 
When the chemicals commence to act one upon the other 
4.5 liter (4.65 quarts) of nitrobenzol are added in very small 
portions at a time, a fresh quantity being only added when 
the previous one has been completely taken up by the mass. 
The addition of the nitrobenzol is so managed that about 
one-half of it remains when the temperature of the mass 
has risen to 158° F. This quantity is then at one time 
brought into the mixing vessel, and the mixing machine 



NITRO-CELLULOSE (GUN-COTTON, PYROXYLIN). 201 

kept going for three hours longer. A thinly-fluid solution 
of the tetra-acetate still containing traces of unchanged 
cellulose and of lower acetates is thus obtained. 

The warm solution is poured into 22.5 liter (23.76 quarts) 
of alcohol, the acetate precipitating thereby as a white, 
finely-flocculent mass, which is separated from the fluid by 
filtration. This flocculent mass is washed with warm alco- 
hol, the washing fluid is added to the mother-lye, and the 
flocculent mass subjected to strong pressure. It is then, 
without previous drying, comminuted, stirred together with 
water, and boiled in the latter until the last traces of the 
solvent have been evaporated. The mass is then again 
filtered, washed first with warm water acidulated with a 
small quantity of hydrochloric acid to remove the last 
traces of the magnesium salt, and then with pure warm 
water, until the fluid running ofl" shows a neutral reaction. 
It is then again subjected to pressure and finally dried at 
a temperature not exceeding 176° F. Of the homologues 
of nitrobenzol, Henckel-Donnersmark has used with equal 
success o-nitrotoluol, p-nitrotoluol, o-nitro-ethylbenzol and 
the nitroxylols and nitrocumols from isopropyl-benzol. 

The composition of cellulose tetra-acetate corresponds to 
the formula C6H605(C2H30)4. The combination is in- 
soluble in methyl alcohol, ethyl alcohol, ethyl acetate, amyl 
acetate, acetones and ether ; it dissolves in ethyl-benzoate, 
chloroform, glacial acetic acid and nitrobenzol. The solu- 
tion in nitrobenzol congeals on cooling to a solid, perfectly 
transparent jelly. 

When a solution of cellulose tetra-acetate is poured upon 
a glass-plate and allowed to evaporate, the combination is 
left behind in the form of laminae of extraordinary trans- 
parency which show considerable solidity even when just 
of such a thickness as still to exhibit the iridescence of very 
thin layers. Towards the action of chemicals, the combi- 
nation shows a degree of indiflFerence which considerably 
surpasses that of nitro-cellulose, it being not attacked by 



202 CEX,LULOSE, AND CELLULOSE PRODUCTS. 

alkalies, which produce no effect whatever even at a higher 
temperature. The combination is only destroyed by boil- 
ing it for several hours in alcoholic soda lye, cellulose re- 
maining behind which, however, retains the form of laminae, 
as well as the transparency. 

One property of the combination which may perhaps be- 
come of great technical importance, is its insulating power, 
which is better than that of rubber or gutta-percha. The 
acetate softens only at about 302° F., and is not inflam- 
mable. 

The great chemical indifference of this substance and its 
extraordinary insulating power may secure for it consider- 
able application in the electrical industry. For many pur- 
poses it might also serve as a substitute for celluloid, 
especially in cases where the use of this material is excluded 
by reason of its great inflammability. Since, as previously 
mentioned, very thin, but nevertheless very solid, laminae 
can be obtained by the evaporation of dilute solutions of 
the ester, such solutions might prove very suitable for 
lacquering metals to protect them from atmospheric action. 

According to L. Lederer an acetyl derivative of cellulose 
is prepared by bringing hydro-cellulose in contact with sul- 
phuric acid and acetic anhydride at a temperature, which 
should not be much above 158° F., the process being as 
follows : The cellulose is allowed for a few minutes to re- 
main in contact with dilute (3 per cent.) sulphuric acid. 
It is then pressed out, dried and heated for three hours at 
158° F. Four times the quantity of acetic anhydride is 
then poured over it. A vigorous disengagement of heat 
immediately takes place, and the heat in the interior of the 
closed vessel must be so moderated by cooling that it does 
not exceed 158° F. The hydro-cellulose is gradually dis- 
solved and when reaction is complete, the mass is mixed 
with water, thoroughly washed, and dried. 

The acetylated cellulose thus obtained forms a white 
powder of a gritty nature, soluble in chloroform or nitro- 



NITRO-CELLULOSE (GUN-COTTON, PYROXYLIN). 203 

benzol. According to Lederer, the acetyl-cellulose prepared 
in the manner above described, is especially suitable as a 
substitute for collodion, and for the preparation of articles 
resembling celluloid in appearance, but distinguished from 
it by being perfectly free from odor aiid not being inflam- 
mable. 

Lederer has later on modified his process by submitting 
the mass, after adding the acetic acid, to uninterrupted 
mechanical manipulation, the temperature, by constant 
cooling, being prevented from rising above 86° F. The 
mechanical manipulation is continued until the mass pre- 
sents the appearance of transparent paste, when, by the 
addition of water, the acet34-cellulose is separated and fur- 
ther worked. 

CELLULOSE BUTYRIC ESTER. 

Cellulose tetra-butyrate or cellulose butyric ester is pre- 
pared in a manner analogous to the acetate, and, as regards 
its propQrties, closely resembles the latter, but is distin- 
guished from it by being more readily soluble in the 
solvents above-mentioned, and dissolving also in ethyl ace- 
tate and in acetone. Laminse obtained from the butyrate 
by allowing solutions of it to evaporate, are somewhat softer 
and more flexible than laminse from the acetate. 

In addition to the above-mentioned esters, Henckel- 
Donnersmark has prepared a series of similar combinations, 
for instance, the double ester — cellulose aceto-butyrate — 
further, cellulose palmitate, cellulose phenyl-acetate, etc. 
As regards their properties, these combinations show a cer- 
tain resemblance to those previously described. Thus far, 
no application of them in the industries has become known. 

" SOLID SPIRIT." 

A peculiar use is made of cellulose acetate, according to 
statements by the " Farbenfabriken," formerly Fr. Boyer & ^^^f 
Co., for the purpose of bringing alcohol into a solid form — 



204 CELLULOSE, AND CELLULOSE PRODUCTS. 

solid spirit. For the preparation of this peculiar product, 
100 grammes (3.52 ozs.) of cellulose tri-acetate are dissolved 
in 500 grammes (17.63 ozs.) of glacial acetic acid and the 
solution is quickly brought into 2 liters (2.113 quarts) of 
alcohol. Cylindrical structures of a gristly nature are 
formed from which the excess of glacial acetic acid and 
alcohol is removed by pressure. They are then dried in 
the air and kept in closed vessels for use. When heated 
the product does not melt, and when ignited, burns uni- 
formly without leaving a residue. 



IX. 

ARTIFICIAL SILK. 

The substance to which the general term silk has been 
applied is the product of the larvae or caterpillars of different 
Lepidoptera of the genus Bombyx, and of a few other varie- 
ties. When the larva has attained its period of full growth, 
it contains in large vessels, almost occupying its entire 
body, a glutinous fluid which is either colorless or yellow, 
or sometimes orange-red. These vessels are by means of 
very small apertures connected with a spinner on the pos- 
terior of the larva, and while the latter spins its cocoon the 
glutinous fluid passes in unbroken lines through the aper- 
tures of the spinner. 

The glutinous fluid immediately coagulates under con- 
tact with air to a very thin thread, which is either colorless, 
yellow or orange-red, and represents the raw silk. How- 
ever, the latter does not consist of a uniform mass, but of 
two distinct bodies. The outer layer is gelatinous and 
gummy, forming the so-called silk-glue, and has to be re- 
moved previous to the further manipulation of the raw silk. 
The core enclosed by this outer layer is the actual silk sub- 
stance, or sericin, or fibroin. In addition to these substances, 
several other bodies, such as albumen, coloring matter, wax 
and fat, occur in silk. The composition of raw silk is, 
therefore, quite complex, and consists, as a rule, of 20 per 
cent, of the gelatinous substance ; 53 per cent, of actual silk 
substance or sericin ; 24 per cent, of albuminous combina- 
tions, and 3 to 4 per cent, coloring matter, fat and wax. 

By a special operation, called scouring or boiling, the 
raw silk is deprived of all other substances except the seri- 

(205) 



206 CELLULOSE, AND CELLULOSE PRODUCTS. 

cin or fibroin, when it can be further worked by mechani- 
cal means. This operation is generally effected by repeat- 
edly boiling the raw silk with soap solutions. 

Viewed under the microscope, a thread of silk freed from 
its envelope of gummy matter appears as a massive cylinder 
(without cavity), resembling in its appearance a glass rod, 
and showing here and there very slight cross-stripes. The 
diameter of the individual threads is very slight, vary- 
ing according to the degree of fineness of the silk between 
2-V and ^V of a millimeter. Notwithstanding this slight 
thickness, silk threads possess an uncommonly high degree 
of strength and elasticity by far surpassing in this respect 
all other textile fibres. 

Silk being not available in unlimited quantities and the 
demand for it being constantly on the increase, chemists 
have for a long time endeavored to produce it by artificial 
means, but the results have always proved unsatisfactory. 
However, efforts to obtain masses for the production of 
threads which, as regards fineness and lustre, closely re- 
semble actual silk and can be spun and twisted, have been 
more successful, but none of these substitutes for silk can, 
as regards strength and elasticity, compare with the natural 
})roduct, even the best of them being in this respect far in- 
ferior to it. 

VARIETIES OP ARTIFICIAL SILK. 

Three varieties of silk-substitutes or artificial silk may at 
present be distinguished and according to their origin may 
be designated as cellulose-silk, collodion-silk, and glue- or 
gelatine-silk. 

As the matter stands at present, pre-eminence above all 
other substitutes has to be given to collodion-silk, while 
glue-silk decidedly occupies the lowest place. However, 
cellulose-silk might in the future take precedence over 
collodion-silk, it possessing decided advantages over the 
latter. 



1- J^RTIEICIAL SILK. 207 

With reference to the historical development of the artifi- 
cial silk' industry, the' French chemist M. de Chardonnet 
was the first to occupy himself successfully with this sub- 
ject. As early as 1884 he deposited with the French 
Academic des sciences a sealed document, which, was opened 
November 7, 1887, and, bore the title Sur une matih-e textile 
artificielle resemhlant d la soie (on an artificial textile sub- 
stance resembling silk). 

The process for the production of a textile substance 
resembling silk suggested, in 1889, by Du Vivier, and 
designated by him as soie de France, can only be considered 
a modification of Chardon net's method. Du Vivier, as well 
as Lehner, uses solutions of nitro-cellulose for the produc- 
tion of textile threads, this being also the pith of the first 
invention, collodion being Chardonnet's initial material. 

Lehner also starts off with nitro-cellulose, but employs 
for its solution substances difi"ering from those used by 
Chardonnet, and mixes this solution with silk-fibroin pre- 
pared from silk waste, or with solution of artificial rubber 
prepared from drying oils. The fluid pressed into the form 
of a thread is conducted into a bath of oil of turpentine, or 
of a mineral oil, in which it coagulates, and the thread thus 
obtained, which is still soft and viscous, is stretched pre- 
vious to being reeled up. 

A. Millar utilizes for the production of textile threads the 
property of glue solution mixed with potassium dichromate, 
becoming insoluble on exposure to light. For this purpose 
a clear solution of gelatine is mixed with solution of potas- 
sium dichromate, the solutions being prepared in the pro- 
portion of 100 parts of gelatine to 2 or 2| parts of potassium 
dichromate. The fluid should only contain sufficient water 
to emerge from the narrow spinning apertures in the form 
of a viscous thread, which on exposure to light becomes 
insoluble. 

Hummel, of Leeds, converts pure gelatine solution into 
threads, dries them and prepares from 16 to 18 such 



208 CELLULOSE, AND CELLULOSE PRODUCTS. 

threads, skeins, which are exposed to the vapors of formalin, 
whereby the gelatine is deprived of its solubility in water. 

Comparative experiments have shown that threads pre- 
pared from glue (gelatine) possess a comparatively high 
degree of brittleness, and in addition have the very dis- 
agreeable property of swelling up very much in moist air. 

Cadoret uses in his method an intermediary between 
Chardonnet and Millar's processes. He dissolves dinitro- 
cellulose in a mixture of ether and acetic acid, and mixes 
this solution with glue solution or albuminous substances, 
so that a fluid is formed which can be drawn out to thin 
threads. The latter acquire solidity by being drawn through 
a tannin solution, by which the glue substance or the albu- 
men is transformed into an insoluble body. The thread 
obtained by this process consists, therefore, of a mixture of 
dinitro-cellulose and the combination of tannin and glue, or 
albumen. 

The methods according to which textile threads are pre- 
pared from pure cellulose instead of nitro-cellulose difi^er 
^essentially from those mentit^ned above. Several processes 
in this direction have becorae%nown, each of which may, 
however, be considered as originM, though of greatest im- 
portance is perhaps the method according to which a solu- 
tion of cellulose in cuprammonium is <p«^pared, and the 
cellulose again separated in the form of fine threads. 
Several such processes for the preparation of textile threads 
from cellulose are known, but only one of them has thus far 
been permanently introduced in practice, this being the in- 
vention of Dr. Hermann Pauly, of Gladbacb, which is at 
present carried on on a large scale. A process in which the 
use of nitro-cellulose is also avoided has been proposed by 
Langhaus. It consists in the main, in kneading cellulose 
with sulphuric and phosphoric acids into a doughy mass, 
which is diluted with sufficient phosphoric acid to form a 
viscous mucilage capable of being spun. No particulars of 
the availability of this process on a large scale are known. 



ARTIFICIAL SILK. 209 

but it will very likely not become of practical importance, 
if for no other reason than that in cuprammonium and vis- 
cose we have materials which allow of a more easy manipu- 
lation of the mass than is the case when highly concentrated 
acids have to be used for its preparation. 

By reason of its cheapness and safety, an excellent method 
for the preparation of silk-like threads is the one in which 
viscose solution is used, it being possible, even at the pres- 
ent state of the process, to produce textile threads which, as 
regards beauty, are not inferior to Chardonnet silk. From 
the present state of the manufacture of textile threads by 
artificial means, it would seem very probable that Char- 
donnet's process can gain a permanent position in practice 
only when the skeins can be successfully deprived of their 
great inflammability. As regards the methods in which 
cellulose solutions are worked, the process in which cup- 
rammonium is employed as solvent, as well as the one with 
viscose, appears to have a great future before it. 

It may here, however, be most emphatically stated that 
for all that, the services rendered by Chardonnet in creating 
this entirely new branch of industry are not the less great, 
because he not only made the first suggestions, but per- 
fected the mechanical part of the entire manufacture so 
that, in this respect, the work of all inventors after him has 
been essentially facilitated. 

CHARDONNET ARTIFICIAL SILK. 

According to Chardonnet's original patent, the process of 
preparing textile threads is as follows : One hundred 
grammes (3.52 ozs.) of pyroxylin together with 10 grammes 
(0.35 oz.) of a reducing metallic protochloride, such as 
protochloride of iron, chromium, manganese or tin, and 0.2 
grammes (3.08 grains) of an oxidizable base, such as, for 
instance, quinine, aniline or rosaniline, are dissolved in a 
mixture of 40 parts of ether and 60 parts of alcohol, and a 
coloring substance is added to the warm solution. This 
14 



210 CELLULOSE, AND CELLULOSE PRODUCTS. 

fluid is pressed through a narrow tube, which is surrounded 
by cold water. The thin thread thus obtained coagulates 
immediately on the surface, while the interior still remains 
liquid. Hence, previous to complete coagulation, this 
thread may be stretched, and this is done so far as the 
tenacit}'' of the substance will permit without tearing the 
thread. The finished thread is then dried and reeled up. 
- Based upon this method, the merest outlines of which arc 
given above, several factories are at present working in 
France, and in Switzerland, and one in England, and the 
establishment of others is said to be in contemplation. 

Regarding the practical application of Cliardonnet's 
process, the following details have become known : 

Perfectly pure cellulose always serves as raw material, 
and cellulose of any derivation may be used, provided it 
has been sufficiently purified. However, it has been shown 
by comparative experiments that the product obtained from 
cellulose prepared from wood is far inferior to others as 
regards purity and beauty of the white color, as well as 
tenacity. Hence in factories working according to Char- 
donnet's process, pure cotton is used as the starting point 
in the manufacture. The cotton is first carefully cleansed 
by mechanical means and then further chemically purified 
by weak alkaline solutions, so that it may be considered 
pure cellulose. It is finall}^ loosened up in a carding 
machine, and then subjected to nitration. 

NITRATION OF THE COTTON. 

The nitrating fluid is prepared from nitric and sulphuric 
acids, great importance being attached. to its being always 
of exactly the same composition. This also contributes to 
the nitro-cellulose showing at all times the same composi- 
tion, which is still further promoted by constantly executing 
all the operations during nitrating according to exactly the 
same plan. 

Fifteen parts of fuming nitric acid, of 1.52 specific gravity, 



ARTIFICIAL SILK. 211 

and 85 parts'^of sulphuric acid are used. The mixture is 
prepared in the morning, and such care is exercised that 
even the content of moisture in the air of the previous night 
is taken into consideration, because in damp nights the 
sulpliuric acid absorbs somewhat more water than in dry 
nights ; hence, in the first case, a somewhat larger quantity 
of sulphuric acid has to be taken.* 

Stone-ware pots, each holding about 40 quarts, are used 
for nitrating vessels, and 8.8 lbs. of dry cotton are brought 
into each pot, and 35 quarts of acid mixture are imme- 
diately poured over them. The pots are placed under a 
contrivance for carrying off the vapor evolved. Imme- 
diately after the acid mixture has been poured over the 
cotton, the contents of the pot are thoroughly stirred, so 
that all portions of the cotton become completely moistened 
with the fluid. The pots are then covered with glass plates. 

The time during wliich the cotton remains in contact 
with the acid depends materially on the temperature of the 
air. It is also stated that the content of moisture in the air 
is also of- influence, but this appears not quite clear because 
gases endeavoring to escape outward hang constantly over 
the fluid in which the cotton is immersed and, furthermore, 
the pots are covered with glass plates. If the content of 
water in the acid has been too large, the nitrated cotton 
does not completely dissolve, and if the temperature has 
been too high, a portion of the cotton is entirely destroyed. 
To obtain a thoroughly uniform product it would, therefore, 
seem advisable alwaj^s to use an acid mixture of one and 
the same temperature and to place the nitrating vessels in 
a large holder in which a strong current of cold water con- 
stantly circulates. By working in this manner there will 
be no difficulty, after a few experiments, to determine ac- 

* If the sulphuric acid be kept in vessels closed air-tight, moist air exerts no 
influence whatever upon it, and it would seem that these statements are only 
made for the purpose of representing to the public the manufacture as a matter 
of particular difficulty. 



212 CELLULOSE, AND CELLULOSE PRODUCTS. 

curately, within a few minutes, the time required for nitra- 
tion. (Compare as regards this subject, the investigations 
of G. Lunge and J. Bebie previously referred to.) 

When nitration has been correctly carried on, the struct- 
ure of the cotton shows no change, it being only somewhat 
coarser to the feel and more brittle. The physical behavior 
of the nitrated cotton exhibits, however, a very essential 
change, especially as regards its behavior towards polarized 
light, which is closely connected with the degree of nitra- 
tion, though the latter may also be established by the di- 
rect determination of the nitric oxide formed from a weighed 
quantity of nitro-cellulose. However, the physical exami- 
nation being less troublesome and, what is the main point 
in this case, requiring but little time, the degree of nitra- 
tion is determined with the assistance of the polariscope. 
Chardqnnet, in compiling a series of comparative experi- 
ments in the chemical and optical w^ay, arrived at the fol- 
lowing results : 

1. Nitration has progressed to the formation of cellulose 
tetranitrate, corresponding to the development of 110 cubic 
cm. nitric oxide from every 1 g. of nitrated cotton. At this 
stage nothing striking is seen in the polariscope except a 
few large fibres of a shriveled-up appearance. 

2. The polariscope shows the above-mentioned fibres to 
be present in larger numbers and already mixed with iri- 
descent fibres. The product yields 145 cubic cm. nitric 
oxide, and is cellulose hexanitrate. From 146 cubic cm. 
nitric oxide up, the fibres become more uniformly gray, 
this continuing to 160 cubic cm. 

3. From 160 cubic cm. on — cellulose heptanitrate being 
now present — up to 180 cubic cm., the color, when the mass 
is tested in the polariscope, turns from straw-yellow to 
orange-red. 

4. When the quantity of nitric oxide evolved becomes 
greater than 160 cubic cm., the mass is first colorless, then 
violet, dark-blue and pale-blue, the latter color becoming 



ARTIFICIAL SILK. 213 

the more pronounced the further nitration progresses. 
When, in polarized light all the fibres appear uniformly of 
a pale-blue color, it is an indication of nitration being 
complete. 

The cotton is then lifted from the nitrating vessel, 
allowed to drain off, and the adhering acid removed by- 
means of a hydraulic press. The acid thus recovered is 
mixed with an adequate quantity of fresh acid and again 
used for nitration. The manipulation in the hydraulic press, 
of the nitrated cotton, saturated with acid, creates difficul- 
ties in so far that the metal parts of the press are strongly 
attacked. This is prevented by coating them with lead, 
plates of the same material being also used for covering the 
floors of the rooms in which acid is handled. 

The gun-cotton comes from the hydraulic press in the 
form of solid cakes, which are immediately comminuted in 
the hollander, and washed. The hollander most suitable 
for this purpose is furnished with a horizontal shaft around 
which stirring paddles revolve. The size of the machine 
should be such that 88 lbs. of dry material, as it comes 
from the press, can at one operation be worked. 

Washing the nitrated cotton is an operation of great im- 
portance, the last traces of acid having to be removed by it. 
The washing process requires from 10 to 12 hours, and dur- 
ing this time the water has to be changed up to sixteen 
times, 22 gallons of water being calculated on for every 2.2 
lbs. of dry material. 

The nitro-cellulose having been sufficiently washed is 
returned to the hydraulic press, and its content of water 
reduced b}^ pressure to 3G per cent., it remaining in this 
condition until after it is spun, when it is completely dried. 
This high content of water renders it perfectly safe, and for 
further working it is simply kept in vessels protected from 
dust. 

PREPARATION OF THE COLLODIOX SOLUTION. 

The solution of the nitro-cellulose in the mixture of 



214 CELLULOSE, AND CELLULOSE PRODUCTS. 

alcohol and ether is effected in a horizontal Iron cylinder 
lined with tin, and capable of revolving around its longi- 
tudinal axis. A mixture of equal .parts of 95 per cent. 
alcohol and ether is used as solvent, and about 100 quarts 
of the mixture are employed for every 48.4 lbs. of dry 
nitro-cellulose. 

The vessel containing the nitro-ccllulose and the solvent 
is uninterruptedly kept slowly revolving by means of a 
mechanical contrivance until solution is complete, the time 
required being from 15 to 20 hours. A small quantity of 
the fluid is from time to tune taken from the vessel by 
means of ar test-cock, and when it appears perfectl}'- clear, 
without any turbidity caused by minute flakes, the solution 
is of the proper quality. 

However, the viscous solution nevertheless contains un- 
dissolved or* incompletely-swollen fibres imperceptible to 
the naked eye, by which the production of an entirely 
uniform thread in any desired quantity would be rendered 
impossible. For the removal of these minute fibres the 
solution has to be filtered. However, with a fluid of the 
viscous nature of nitro-cellulose solution, this operation can 
only be effected with the use of very strong pressure upon 
the surface of the fluid, a pressure of 30 to 60 atmospheres 
being, according to experience, required for the purpose. 

The filtering contrivance consists of a cylindrical vessel, 
the filtering material being placed upon the bottom, a layer 
of fine cotton waddhig, 0.39 to 0.59 inch thick, being used 
for the purpose. This layer of cotton wadding is enclosed 
between two sheets of finest silk gauze, and covered on both 
sides with tinned metallic cloth. The filter has a capacity 
of about 100 quarts of nitro-cellulose solution, and having 
been charged with fluid and closed, air under pressure is 
introduced through a pipe on the top, the pressure being 
gradually increased to such a degree as required to cause 
the filtered fluid to run off in a sufficiently thick stream. 

Uefore beino- further worked, the filtered fluid is for a 



ARTIFICIAL SILK. 215 

certain time kept in glass carboys, each holding about 50 
quarts, it having been shown by experience that, as regards 
its capacity of being spun, it thereby gains considerably in 
quality. The cause of this phenomenon is very likely 
found in the fact that during storing, a thorough intermix- 
ture of all the particles of fluid takes place so that the 
smallest differences in the quality of the separate portions 
of fluid are removed. Hence, in order to have constantly 
collodion of the best quality, a certain quantity should 
always be kept on hand, so that it may be stored for a 
sufficiently long time previous to being spun. 

SPINNING THE COLLODION. 

For the production from the perfectly homogeneous 
collodion of a thread representing artificial silk, an appar- 
atus has to be used, which is furnished with extremely 
narrow apertures through which the collodion solution is 
pressed. The thread suspended free in the air yields, by 
evaporation, the ether and alcohol, and is in a short time 
changed to a solid thread, which, however, still possesses 
sufficient elasticity and plasticity to allow of its being 
drawn out by slight tension to a still thinner thread, which 
is then reeled up and further worked. 

For the production of the thin threads, sieve-like metal 
plates ma}'^ be used, or, what would appear more suitable, 
narrow glass nozzles. The disposition of the spinning 
apparatus used in factories arranged according to Char- 
donnet's S3'stem is as follows : 

The collodion to be worked is contained in a vertical, 
tin-lined steel cylinder, provided on top with a pipe through 
which air under pressure maj'^ be introduced. To the 
lower end of the cylinder is secured a steel pipe furnished 
with glass spinners placed at a distance of about 0.78 inch 
one from the other. 

•The glass spinners are made by drawing out glass tubes 
over a glass-blower's lamp, so that the lower opening has a 



216 CELLULOSE, AND CELLULOSE PRODUCTS. 

diameter of only -g^-^ millimeter. The uniformity of the 
threads being, of course, dependent on the aperture of all 
the spinners having the same diameter, great care has to be 
exercised in their manufacture. Every finished spinner 
must be examined, as to its diameter, with the microscope, 
and only those are available which by microscopical meas- 
urement show uniformity of diameter, all others with wider 
or narrower apertures being rejected as useless. 

The spinners of proper diameters are cemented in a metal 
frame and, together with the latter, secured to the horizon- 
tal pipe of the apparatus. By gradually increasing the air-, 
pressure upon the surface of the collodion, it is finally 
increased to such a degree that the collodion is with the 
proper velocity pressed from the spinners. The pressure 
required for this purpose depends on the viscosity of the 
collodion, and ranges from 40 to 50 atmospheres. 

The spinning apparatus was originally so arranged that 
the fine threads pressed from the spinners passed into water 
mixed with ^ per cent, of nitric acid. However, this was 
found to be entirely superfluous ; the threads could be di- 
rectly worked as they came from the spinners, coagu- 
lating almost immediately under contact with air. With 
the assistance of contrivances closely resembling the reels 
on which natural silk is wound from the cocoons, the 
threads are caught and reeled up. A counter records the 
number of revolutions made by the reel, and the diameter 
of the latter being known, the length of thread, after the 
reel has revolved for a certain time, is also known. In this 
manner an unbroken thread many thousand meters long 
may be produced, but, as a rule, only 500 meters (546.81 
3^ards) are wound on one reel, when the thread is taken off^ 
and brought together to a skein. 

By the solidification of the threads, the total quantity of 
alcohol and ether contained in the collodion passes in the 
form of vapors into the air. For the removal of these 
vapors the spinning room should be provided with a very 



ARTIFICIAL SILK. 



217 



powerful airing contrivance by which the air loaded with 
vapors is carried off and replaced by fresh air from the out- 
side. For this purpose a suitable number of electrically- 
driven ventilators revolving with great rapidity are, as a 
rule, fixed in the ceiling of the spinning room. 

THE SPINNING APPARATUS. 

The main features of the arrangement of Chardonnet's 
spinning apparatus are shown in Figs. 34 and 35. The 
narrow glass tubes a, which serve as spinners, are sur- 




Chardonnet's apparatus for the preparation of artificial silk. 



rounded by a pipe, K, filled with water, and are fixed upon 
the joint pipe, 5, which is surrounded by two channels, C, 
in which hot water circulates. The lower aperture of each 
spinner is surrounded by two curved spring-blades which 
form pincers, m. By means of the joint lever o and the 



218 



CELLULOSE, AND CELLULOSE PRODUCTS. 



curved arms p j), these pincers oscillate constantly up and 
down over the reels or spools on which the threads are 
wound, so that in case one of the threads should hreak, it is 
immediately caught by them and returned to the reel or 
spool. So long as the thread runs without breaking, the 
pincers move up and down empty. The revolving brush, 
H, cleans the pincers on the upper end of the lever. 

Fig. 35. 




Chardonnet's apparatus for the preparation of artificial silk. 



The spindles of the spools, R, which serve for winding up 
the threads just spun, sit upon the loose cheeks of the revolv- 
ing axle 0. They carry small rolls V, which are in contact 
with the surfoce of smaller sheaves A. By this arrangement 
the simultaneous revolution of all the spools is secured, and 



ARTIFICIAL SILK. 219 

the cheeks for replacing the full spools with empty ones are 
also simultaneoush'^ moved. The entire spinning apparatus 
is enclosed in a glass case, L F, through which a current of 
warm air is constantly passed for the purpose of forcing the 
vapors of alcohol and ether to the condensing vessels. 

The first of these condensing vessels contains a solution 
of soda in water upon which the condensed alcohol floats. 
The vapors escaping from this vessel hold much* ether, but 
very little alcohol, and are conducted through several vessels 
containing sulphuric acid which absorbs the total quantity 
of vapors. This sulphuric acid is ntilizcd for the prepara- 
tion of ether. 

The threads obtained in the manner above described con- 
sist of nitro-cellulose, to which, however, still adheres. almost 
the entire quantity of water (about 3G per cent.) originally 
remaining in the pressed nitro-cellulose. This content of 
water is left in the threads till they are finished to prevent 
otherwise possible spontaneous ignition. 

The next step in the operation consists in throwing or 
twisting the individual threads, and finishing them by dr}'^- 
ing. The latter operation is effected by taking the thrown 
threads from the reels and passing them through a room 
the temperature of which is kept at 113° F. Wliile the 
threads pass through this room all the water still adhering 
to them is evaporated, complete drying being insured by 
keeping up, in addition, a strong current of air during the 
quite rapid passage of the threads tlirough the room. 

Notwithstanding its beauty, the artificial silk thus ob- 
tained would not be of any practical use if it were left in 
this condition. It consists of nitro-cellulose and being, 
therefore, highly inflammable, a fabric made of it would 
in an infinitely short time be reduced to ashes by a spark 
falling upon it. The artifical silk is therefore subjected to 
an operation to which the term denitratlon has been applied, 
its object being to reconvert the nitro-cellulose into ordinary 
cellulose. 



220 CELLULOSE, AND CELLULOSE PRODUCTS. 

This denitration constitutes one of the most difficult por- 
tions of the manufacture of artificial silk, because it has to 
be done as completely as possible, without, however, im- 
pairing in the slightest the lustre and smoothness of the 
threads. 

Denitration may be effected by conducting the threads of 
nitro-cellulose through solutions of alkaline sulphides, and 
the sulphides of potassium, sodium or ammonium may be 
used for this purpose. However, ammonium sulphide 
seems to be most suitable, it causing very complete denitra- 
tion without attacking the silk itself. The different factories 
keep the composition of the fluids used by them for denitra- 
tion secret, but a fluid of the proper quality may be readily 
prepared with the use of ammonium sulphide obtained by 
saturating concentrated ammonia with sulphuretted h3'dro- 
gen, and allowing it to stand until it has become yellow. 
Ammonium sulphide which has turned yellow contains the 
polysulphides of ammonium in solution, and they appear 
to be especially effective in denitration. 

The ammonium sulphide obtained in the above manner 
is, of course, too concentrated for use, and to obtain a deni- 
trating fluid of the proper quality, fluids consisting of water 
to which a certain percentage of concentrated ammonium 
sulphide has been added, must be employed. The opera- 
tion has also to be effected at a certain temperature, deni- 
tration taking place much more rapidly at a higher tem- 
perature than at one but a few degrees lower. 

The correct composition of the denitrating fluid may be 
recognized, on the one hand, by the appearance of the de- 
nitrated threads under the microscope ; they should, after 
denitration, be as smooth, uniform and lustrous as before. 
If the fluid has been too concentrated and acted too vigor- 
ously, it is immediately recognized by the appearance of 
the threads under the microscope ; they are lustreless, dull 
and here and there even corroded. The correct composi- 
tion of the denitrating fluid may, on the other hand, also 



ARTIFICIAL SILK. 221 

be established by chemical analysis, which should show 
that the silk contains no nitric oxide whatever, or that the 
quantity of its content has been reduced to a minimum. 

By denitration the silk acquires a yellow color and has 
therefore to be subjected to a bleaching process, a small 
quantity of chloride of lime and hydrochloric acid being 
used for the purpose. In factories working according to 
Chardonnet's system, 400 grammes (14.11 ozs.) of chloride 
of lime and 800 grammes (28.21 ozs.) of hydrochloric acid 
for 16 kilogrammes (35.2 lbs.) of artificial silk are found 
sufficient. 

The bleached skeins of silk are freed by careful washing 
from adhering bleaching agent, then, as far as possible, de- 
hydrated in a centrifugal, and finally dried. Tlie product 
thus obtained is of a pure-white color, has the feel of natural 
silk, but surpasses the latter in beauty of lustre. 

PREPARATION OF COLORED ARTIFICIAL SILK. 

Colored artificial silk may be prepared in two different 
ways, namel}', by direct coloring while preparing it, or by 
dyeing the finished skeins. The first-named process has the 
appearance of being the more simple one, thus deserving 
the preference, but it has been learned by practical exper- 
ience that the more suitable way is to prepare first the white 
silk, and then follow the same method used in dyeing na- 
tural silk. 

Dyeing the artificial silk while in the course of prepara- 
tion is effected by simply dissolving the coloring matter in 
the collodion, the readily soluble aniline colors being, by 
reason of their richness, especially suitable for the purpose. 
The coloration of the collodion has to be very intense, so 
that every one of the extremely thin threads appears suffi- 
ciently dyed. 

The mixture of the coloring matter with the collodion 
has to be effected before the latter is filtered, this being the 
easiest way of coloring the solution uniformly throughout, 



222 CELLULOSE, AND CELLULOSE TRODUCTS. 

SO that the threads al\va3-s show exactly the same color. 
However, with the use of colored solutions the contents of 
at least one cylinder have to be used all at once, and thus 
the quantity of silk of a determined color is quite limited. 

For this reason the production of silk from colored solu- 
tions has been almost entirel}^ abandoned, white silk only 
being prepared, which, after having pnsscd through the 
processes previously described, is dyed like natural silk. 
Artificial silk prepared from nitro-cellulose possesses the 
property of readily fixing the coloring matter, and nearly 
all shades of color can be produced by simply immersing it 
in the dye solutions, the process being exactly the same as 
that emploj'ed in dyeing natural silk, and at present aniline 
colors are preferably used. 

A comparative table of the properties of artificial silk 
prepared according to the various methods will be given 
later on, and hence those of Chardonnet silk need here only 
be briefly referred to. As regards lustre, it surpasses by far 
the finest qualities of natural silk, and when worked, either 
in an uncolored or colored state, into fabrics, it produces 
more beautiful effects than tissues of genuine silk. How- 
ever, while the latter is distinguished by great strength and 
tenacity, artificial silk possesses these properties in a far less 
degree. By taking the elasticity of natural silk at 100, 
that of the best quality of Chardonnet silk is at the utmost 
60, hence only about two-thirds. Fabrics made of artificial 
silk alone would not prove very durable, and hence in 
weaving them, pure silk or another fibre is generally used 
for the warp and artificial silk for the woof 

Du vivier's artificial silk. 

This process for the preparation of a product closely 
resembling in appearance natural silk, was made known in 
1889. It differs only in a few details from Chardonnet's 
method, nitro-cellulose being also used as the basis-material 
for its preparation. 



ARTIFICIAL SILK. 223 

The method of preparing this product known as soie de 
France is briefly as follows : 

Cotton or in place of it, artificially-prepared cellulose is 
in the ordinary manner puritied by treatment with alkalies 
— either soda or ammonia — and then converted into nitro- 
cellulose. However, instead of using a mixture of nitric 
and sulphuric acids, Du Vivier falls back upon the old 
method of nitration in wliich dry saltpetre and sulphuric 
acid are used as nitrating fluid, and eff'ects the treatment of 
thecelhilose at a comparatively high temperature — 140° to 
176° F. — till trinitro-cellulose is obtained. 

In working with saltpetre and sul})huric acid, potassium 
sulphate is formed. Tliis salt being distinguished by its 
comparatively slight solubility, it can onl^?- with surety be 
removed from the nitro-cellulose by subjecting the latter to 
a thorough treatment with water, and the consumption of 
wash winter must necessarily be still larger than is the case 
in Chardonnet's process. 

The solvent for the nitro-cellulose has to be considered as 
the main feature of Du Vivier's method. He uses for this 
purpose highly concentrated acetic acid (glacial acetic acid) 
in the proportion of 100 parts of it to 7 parts of nitro- 
cellulose. The nitro-cellulose obtained in this manner is 
mixed in varying proportions Avith a fine quality of glue 
(isinglass) and gutta-percha, and then worked into threads. 
The latter are conducted through various baths prepared 
from solutions of metallic salts — alumina salts and subli- 
mate solutions being used — the object of which is very 
likely to transform the glue contained in the mass into an 
insoluble combination. The finished threads have finally 
to be subjected to denitration as, like other nitro cellulose 
silk, it would otherwise be highly inflammable. 

As far as known, Du Vivier's process has not been suc- 
cessfully introduced in practice. Some samples of the silk 
submitted for examination are said to surpass the Char- 
donnet product in beauty of lustre. 



224 CELLULOSE, AND CELLULOSE PEODUCTS. 

Regarding the mechanical part of preparing the threads, 
nothing need to be said here, as, with the exception of 
slight modifications, it can only be carried on in a manner 
similar to that described more fully when speaking of 
Chardonnet's process. 

lehner's artificial silk. 

The third process for the manufacture of artificial silk 
from nitro-cellulose, which has thus far become known, is 
that of Lehner. It is now practically carried on on a large 
scale, and threatens to become a serious competitor of 
Chardonnet's system. 

Lehner also starts with nitro-cellulose capable of com- 
plete solution, but all information regarding the prepara- 
tion of this nitro-cellulose is wanting. According to the 
patent, dated 1890, wood spirit (methyl alcohol) is used as 
solvent for the nitro-cellulose, and to this solution, a solu- 
tion of fibroin is added. The fibroin, i. e., the fibrous 
portion of natural silk, is obtained from waste in silk 
spinning establishments, it being purified and dissolved in 
concentrated acetic acid. 

According to a modification made public later on, in 
place of fibroin solution, solution of rubber prepared from 
drying oils, may be added to the nitro-cellulose solution. 
The solutions mixed in certain proportions — which, how- 
ever, are not given — are pressed through spinners, and 
conducted through a vessel containing petroleum, chloro- 
form, or oil of turpentine. The thread coagulates in these 
fluids so far as to acquire a thick, gelatinous condition, thus 
representing a very viscous mass. This state of the thread 
is utilized to make it still thinner by stretching, when it is 
w^ound on reels. 

According to the present state of the manufacture of 
artificial silk, but two processes for its production from 
nitro-cellulose which can actually be carried on a large 
scale, are known, namely Chardonnet's and Lehner's. It 



ARTIFICIAL SILK. 225 

is scarcely to be expected that another process will be added 
to them, since Pauly's artificial silk and lustra-cellulose pre- 
pared from viscose, compete to such an extent with the 
products prepared from nitro-cellulose, that this competition 
will very likely end in the abandonment of the manufac- 
ture of artificial silk from nitro-cellulose. 

DENITRATION OF ARTIFICIAL SILK. 

The absolute necessity of denitrating artificial silk pre- 
pared from nitro-cellulose is one of the weakest points of the 
entire process, it being extremely difficult to eff"ect denitra- 
tion to the extent required without impairing the beauty of 
the product. 

H, Richter has made exhaustive investigations regarding 
the denitration of artificial silk from nitro-cellulose, and, 
according to his statements, denitration as effected by his 
method, does not impair in any way the qualities of the 
silk as regards lustre, etc. The pith of Richter's method is 
the treatment of the silk with such metallic salts as have 
lower and higher degrees of oxidation, the solutions of 
the lower degree of oxidation being used with the addition 
of an acid. Among the metallic salts adapted for this pur- 
pose, the cuprous compounds are said to be most suitable, 
complete denitration being effected by cuprous chloride and 
cuprous oxychloride. Besides the cuprous compounds, 
there may be used, either by themselves or in a mixture of 
them : Ferrous, manganous, chromous, tungstous, stannous, 
mercurous salts, and the ferro-cyanide and metallic cyanide 
combinations. 

For the purpose of accelerating the denitrating process, 
substances which cause the artificial silk to swell up may 
be added to the fluid and, in addition to alcohol and ether, 
mention is made of a long series of substances as being suit- 
able for the purpose, for instance, oil of turpentine, glycer- 
ine, indifferent hydrocarbons and their derivatives, rubber 
solutions, and particularly isinglass. It is claimed that 
15 



226 CELLULOSE, AND CELLULOSE PEODUCTS. 

such additions cause denitration to progress smoothly and 
completely, and that the full strength of the fibres is pre- 
served. With the use of cuprous salts for denitration, such 
additions are said not to be required. In regard to the 
quantity of acid to be used, it is only necessary to take 
enough of it to convert the lower degree of oxidation into 
the higher one. 

As a special advantage of his process, Richter mentions 
the possibility of recovering the nitrogen compounds, espec- 
ially the nitric oxide, which are separated by denitration. 
However, according to our view of the matter, the recovery 
of the nitrogen compounds would actually pay only when 
denitration is effected with large quantities of artificial silk. 
For this purpose, air-tight vessels would have to be used for 
denitration, from which the nitric oxide evolved is con- 
stantly sucked off, and then oxidized by bringing it in con- 
tact with oxidizing bodies such as hydrogen peroxide or 
solution of potassium permanganate. The nitric oxide may 
also be directly conducted into sulphuric acid and, after 
adding an adequate quantity of nitric acid, this acid may 
again be used as denitrating fluid. The oxy-salts formed in 
denitration may also be reconverted into the lower degree 
of oxidation, so that the operation can be constantly carried 
on with a given quantity of the metallic salt. 

If, for instance, cupric salts have been used, the fluid, 
after denitration, only contains cuprous salt. By adding 
to this fluid common salt and conducting sulphur dioxide 
through it, the cuprous salt is again reduced to cupric salt. 
Reduction is effected in a still more simple manner by plac- 
ing copper plates in the acid fluid. In a similar manner 
the higher degrees of oxidation of other metals may by suit- 
able reducing agents be reconverted into the lower ones, for 
instance, stannic chloride by ferrous chloride. 

Some methods have also been devised with the object in 
view of preparing from the start a product which is not in- 
flammable and, hence, does not require denitration. Such 



ARTIFICIAL SILK. 227 

a process has, for instance, been patented in England, by 
A. Peit, according to which 100 parts of nitro-cellulose, 7 
parts of gum solution and 5 parts of stannous chloride dis- 
solved in benzol are used. What is to be understood by 
gum solution is not entirely clear from the patent specifica- 
tion, and as gum solutions cannot be combined with ben- 
zol to a homogeneous fluid, it may be supposed that rubber 
is meant. It has thus far not transpired whether Peit's 
process has anywhere been introduced in practice. 

From the present state of the industry it has to be 
acknowledged that artificial silk prepared from nitro- 
cellulose is distinguished by a beautiful appearance, as well 
as by relatively great tenacity and elasticity. The mechan- 
ical portion of manufacture has also been brought to such 
perfection as to allow of the production of artificial silk on 
the most extensive scale. 

However, as previously mentioned, the process has one 
weak point, in that denitration is absolutely necessary, and 
by this operation the beauty of the product will remain 
unimpaired only when the greatest care is exercised. The 
particulars regarding the operations of denitration thus far 
made public are only partially satisfactory. 

Particular attention has to be drawn to the fact that the 
production of artificial silk from nitro-cellulose has the 
decided drawback of the operation being by no means 
free from danger to the workmen. Notwithstanding all 
the precautionary measures taken in the factories, spontane- 
ous ignition has frequently occurred, and in one case at 
least it was accompanied by explosive phenomena. That 
there is never absolute safety as regards spontaneous ignition 
is shown by the behavior of nitro-cellulose in drying. As 
mentioned in describing the manufacture of nitro-cellulose, 
the latter becomes electrical so readily that the passage 
over it of a warm current of air may lead to the formation 
of such a large quantity of electricity as to cause the forma- 
tion of a spark. Even if the latter be never so small, it is of 



228 CELLULOSE, AND CELLULOSE PRODUCTS. 

sufficient power to ignite the nearest particles of nitro- 
cellulose, and the ignition of the entire mass must inevit- 
ably follow. Hence, in the production of textile threads 
from nitro-cellulose, special care must be taken that up to 
the time when the threads are subjected to denitration, they 
contain such a large content of water as is consistent with 
the operation, because spontaneous ignition of the nitro- 
cellulose can only under these conditions be positivel}'" 
prevented. In addition to this precautionary measure, 
attention must be paid to the health of the workmen by 
providing means for carrying off the vapors of ether and 
alcohol evolved during the coagulation of the threads. The 
precautionary measures which have to be adopted in this 
respect have been previously referred to. 



X. 

CELLULOSE THREADS. (CELLULOSE ARTIFICIAL 
SILK AND LUSTRA-CELLULOSE.) 

Several methods, according to which it seems feasible 
to convert cellulose into a solution from which textile 
threads may be produced, are at present known, and some 
of them have been applied to the manufacture of textile 
threads on a large scale. As will be seen from the descrip- 
tions given below, these methods possess decided advantages 
over the process in which nitro-cellulose solution is used. 
These advantages are so great that from a purely economical 
standpoint, it may be safely predicted that these methods 
will more and more gain ground, and that cellulose-silk 
will finally be made so cheaply as to exclude the profitable 
production of nitro-cellulose silk. The main advantage of 
textile threads from cellulose is undoubtedly that they are 
no more inflammable than fabrics of any other kind of 
cellulose, for instance, cotton. Another advantage is that 
the manufacture itself is far more simple than can possibly 
be the case with nitro-cellulose. In addition, it may here 
be remarked that, as regards lustre and beauty, fabrics of 
cellulose threads compare favorably with nitro-cellulose silk. 

While cellulose dissolves in a number of fluids, only one 
solvent, namely cuprammonium, need here be considered. 
This combination has for a long time been used by micro- 
scopists for distinguishing vegetable tissues. The object 
under the microscope is moistened with cuprammonium 
solution which causes the portions of tissue consisting of 
cellulose to disappear, they being dissolved in the fluid. 

(229) 



230 CELLULOSE, AND CELLULOSE PRODUCTS. 

The residue remaining behind consists of other combina- 
tions. 

The idea of utilizing the solubility of cellulose in 
cuprammonium for the preparation of textile fibres is of 
modern conception, and to Dr. Hermann Pauldy, of Glad- 
bach, is due the merit of having invented a process by 
which such threads can be produced on a large scale. 

DR. PAULY's ARTIFICIAL SILK. 

The preparation of textile threads (artificial silk) accord- 
ing to Dr. Pauly's method includes a series of operations, 
which, as far as the actual production of the thread is con- 
cerned, may be sub-divided as follows : 

1. Preparation of pure cellulose. 

2. Preparation of a solution of cellulose in cuprammonium 
of such concentration that, when pressed through apertures, 
a thread results which possesses sufiicient tenacity to allow 
of its being stretched lengthwise. . 

3. Separation of the cellulose in the thread. 

4. Washing, drying, throwing of the thin cellulose 
threads. 

To these operations have to be added the preparation of 
the cuprammonium solution and the recovery of the copper 
from the fluids used, the endeavor being made to regain as far 
as possible the entire quantity of copper used in the opera- 
tion so that the same quantity is in constant circulation in 
the factory. 

PURIFICATION OF THE COTTON. 

The cotton to be used has, previous to its solution in 
cuprammonium, to be subjected to a thorough cleansing 
process, this being effected in a manner similar to that pre- 
viously described. Quite pure cotton is washed in a wash- 
ing drum with soda solution, while for less pure material, 
dilute caustic soda solution is used. 

The cotton treated with one of these fluids is whirled in 



CELLULOSE THREADS (CELLULOSE ARTIFICIAL SILK). 231 

a centrifugal, thoroughly washed with water, then again 
w^hirled in the centrifugal, and finally completely dried. 
For the latter purpose artificial heat has to be employed, 
otherwise the cuprammonium solution would be too much 
diluted by the water contained in the cotton, the conse- 
quence of which would be loss of viscosity. 

DISSOLVING THE COTTON IN CUPRAMMONIUM. 

The cotton when perfectly dry is dissolved in cupram- 
monium, the preparation of which will be described later 
on. For 45 to 50 grammes (1.41 to 1.76 ozs.) of cotton, 1 
liter (2.11 pints) of cuprammonium is used, this concentra- 
tion being sufficient to yield a fluid capable of being spun. 

According to statements made public, solution is to be 
eff'ected in an apparatus closely resembling a montejus. 
However, since the latter apparatus consists of only a single 
vessel closed on all sides, in which the fluids are forced up- 
wards through a rising pipe, it would not seem very well 
adapted to the purpose of dissolving the cotton, though it 
might answer for storing the solution till it is to be used. 

For the purpose of dissolving the cotton as rapidly as 
possible in the cuprammonium, a mechanical contrivance 
of such a character is required that the cotton is kept in 
constant motion and that fresh portions of it are continu- 
ally brought in contact with the solvent. 

An apparatus resembling a hollander but constructed in 
accordance with the nature of the mass to be worked in it, 
would appear very suitable for the purpose of dissolving 
the cotton. The elliptical bottom of the trough of the hol- 
lander should be either of wood alone, or preferably, for the 
sake of durability, of wood lined inside with stout copper- 
sheet. The trough should be furnished with an air-tight 
lid to prevent decomposition of cuprammonium by the 
evaporation of ammonia. One of the compartments should 
be furnished with a grinding contrivance consisting of a 
corrugated bottom-plate and a corrugated cylinder revolving 



232 CELLULOSE, AND CELLULOSE PRODUCTS. 

at a short distance above the bottom-plate, and effecting the 
comminution of the mass passing through it. The bottom- 
plate, as well as the cylinder revolving above it, should be 
either of copper or another material not attacked by the 
fluid. Iron or steel is, in this case, entirely excluded, 
because the copper contained in the fluid would be separ- 
ated from it in metallic form. 

Solution is effected by bringing the weighed quantity of 
pure cotton into the hollander, closing the latter, and al- 
lowing cuprammonium solution to run in slowly, the 
mechanism which effects the revolution of the cylinder over 
the bottom-plate being at the same time set in motion. In 
the commencement of the operation only a small quantity 
of the solution should be run in, so that the cotton becomes 
first saturated with it before the entire quantity is intro- 
duced. By the continued tearing between the bottom-plate 
and cylinder, the particles of cotton are uniformly dis- 
tributed throughout the fluid, solution being under these 
conditions effected in the shortest time possible. In prac- 
tice, 10 hours are generally calculated on as being required 
for the preparation of the solution, but with the use of an 
apparatus similar to the one above described, it may be 
effected in a much shorter time. 

The progress of solution is judged by the appearance of 
samples taken from time to time and allowed to stand 
quietly for 10 minutes in a tall, covered glass cylinder. If 
solution has been properly effected, the fluid is perfectly 
clear and of a uniformly blue color without cloudiness. If 
the lower portions of the fluid show a different color, or a 
precipitate is noticed, it is indicative of a considerable por- 
tion of the cotton remaining in an undissolved, or only in 
a very much swollen, state. The manipulation in the 
hollander has then to be continued till the sample shows no 
longer a want of uniformity. 

Although the fluid appears to the eye perfectly uniform, 
it may nevertheless contain considerable quantities of cot- 



CELLULOSE THREADS (CELLULOSE ARTIFICIAL SILK). 233 

ton fibres only very much swollen without being actually 
dissolved. Such fibres would make the solution unsuitable 
for spinning, a viscous fluid absolutely free from solid 
bodies being only adapted for that purpose. Hence, the 
solution must by all means be filtered, filtration being, in 
this case, also effected in an entirely closed apparatus in 
which the fluid stands under such a high air-pressure as to 
be forced through the close pores of the filtering body, a 
substance entirely indiff'erent towards the action of cupram- 
monium being used for that purpose. Cotton is unsuitable 
for a filtering material, since by the action of the cupram- 
monium it would in a short time swell up so much that no 
fluid could be forced through it even by the strongest pres- 
sure. Plates of compressed asbestus-felt with pores suffi- 
ciently close to retain the solid bodies suspended in the 
fluid are very suitable for filtering purposes. The residue 
remaining upon the filter consists chiefly of the more solid 
portions of the cuticles of the cotton fibres and remnants of 
plasma. 

The filter is fitted up in a similar manner to that de- 
scribed under Chardonnet silk. In a boiler-plate cylinder 
stands a vessel of sheet copper which serves for the reception 
of the fluid to be filtered. Upon the bottom of this vessel 
lies the asbestus plate enclosed in two plates of copper-wire 
cloth. Below the filter-plate the copper cylinder terminates 
in a truncated cone and is connected with a copper vessel 
which serves for the reception of the filtered solution. 

The pressure upon the fluid in the vessel is produced by 
compressed air, and should be of sufficient force to effect 
filtration with suitable rapidity. Solutions of cotton in 
cuprammonium being by far less viscous than nitro-cellulose 
solutions, less pressure is required, one or a few atmospheres 
being sufficient. 

If the pipe leading from the filter be allowed to enter a 
montejus, the solution collects in the latter and may be 
raised by air-pressure through the rising pipe of the montejus 
into the vessel in which the spinning apparatus is placed. 



284 CELLULOSE, AND CELLULOSE PRODUCTS. 

SPINNING THE SOLUTION. 

The spinning vessels closely resemble those used in Char- 
donnet's system. They consist of closed sheet-steel cylin- 
ders lined with copper, in Avhich the fluid can be placed 
under increased pressure. 

The contrivance in which the formation of threads is 
effected is, however, of peculiar construction. The solution 
of cotton in cuprammonium is also distributed in a hori- 
zontal pipe to which the spinners are secured, the latter 
being, however, of a characteristic shape. They are placed , 
obliquely and bent slightly upwards, so that the fluid 
emerging from them ascends upwards in an oblique direc- 
tion. The apertures of the spinners lie beneath the level 
of a fluid consisting of water containing 15 per cent, of sul- 
phuric acid. 

The spinners through which the solution passes into the 
dilute sulphuric acid are in construction similar to those of 
the Chardonnet system, but as will be directly explained, 
threads of a considerably smaller diameter than that of their 
apertures can be obtained from them. 

The moment the cellulose solution passes into the sul- 
phuric acid, it is decomposed, a solution of cupric sulphate 
(blue vitriol) and ammonium sulphate being formed. The 
solvent being decomposed, the cellulose must separate in a 
solid state, this separation taking place in the form of a soft 
cylinder of a gelatinous nature which possesses a high de- 
gree of extensibility. This behavior is utilized for making 
the thread still thinner by stretching. 

The threads — usually 18 — as they come from the lead 
trough containing the sulphuric acid are run through a 
glass gatherer or collector, so that the thread thus formed 
is actually composed of 18 separate threads. Back of this 
gatherer, revolves with suitable velocity a glass roll on 
which the thread is wound under a certain tension, thus 
being stretched. The glass roll while revolving is also with 



CELLULOSE THREADS (CELLULOSE ARTIFICIAL SILK). 235 

the requisite velocity moved sideways so that the thread is 
wound up in windings one alongside the other. 

The cellulose, by reason of its larger content of water 
being much too soft to stand rinsing off before being brought 
upon the glass roll, washing has to be effected upon the 
latter itself This is best done by placing a number of 
such glass rolls in a mechanical contrivance, which causes 
them to revolve slowly in a trough constantly supplied 
with fresh water, in which they remain till the last traces of 
sulphuric acid have been removed. 

When washing is finished, the cellulose threads are dried 
at a higher temperature by bringing the glass rolls into a 
drying room. By the slight contraction the threads undergo 
in drying, their fineness and lustre are still further enhanced. 

The further manipulation by mechanical means of the 
cellulose threads prepared in the above described manner, 
is effected in exactly the same way as in silk-spinning 
works. The thread is wound from the glass rolls on spools, 
and thrown. The finished threads suitable for spinning 
may be dyed in the skein. They are mordanted in various 
ways according to the coloring matter to be used, and left 
in the dye bath till the desired tone of color is obtained. 

As compared with the product prepared from nitro- 
cellulose, the properties of the artificial silk, or rather pure 
cellulose, prove ver}' satisfactory. As regards tenacity and 
elasticity, it is at least equal to Chardonnet silk, and pos- 
sesses the rustle characteristic of genuine silk. A special 
advantage of Pauly's silk is found in the fact that its pro- 
duction is free from all danger, no poisonous vapors being 
evolved, and the use of a substance, like nitro-cellulose, 
which is dangerous to handle, is excluded. Finally, Pauly's 
silk does not require denitration, which is absolutely neces- 
sary with the product from nitro-cellulose, and this evi- 
dently constitutes the most valuable feature of the process. 
With reference to the point of expense, it will be seen at the 
first glance on comparing Pauly's method with the nitro- 



236 CELLULOSE, AND CELLULOSE PRODUCTS. 

cellulose process, that the cost of production by the latter 
must be considerably greater, the cellulose having first to 
be converted into nitro-cellulose, and then as far as possible 
again reduced b}' denitration to cellulose. From the ad- 
vantages enumerated here, both as regards manufacture 
and properties, it would seem that Pauly's method will in 
the course of time drive nitro-cellulose silk out of the field. 

E. bronnert's process. 

This method for the preparation of textile threads from 
solution of cellulose in cuprammonium differs essentially 
from Pauly's, the cellulose being first converted into soda- 
cellulose which is effected with caustic soda, and then 
triturated with cupric sulphate (blue vitriol). A double 
conversion takes place thereby, sodium sulphate being- 
formed and a loose combination of cupric hydrate and cel- 
lulose. By treating this combination with ammonia, a 
solution possessing a considerable degree of viscosity, which 
it retains at a higher temperature, is obtained, and conse- 
quently it yields good threads capable of being spun. 

In carrying out the process, it is necessary to use the 
separate substances according to molecular weights. For 
162 parts by weight (1 molecule) of dry cellulose in a 
finely divided state, 80 parts by weight of pure sodium 
hydrate dissolved in 500 parts by weight of water are used^ 
the cellulose being intimately mixed with the fluid. In 
the course of an hour, 249 parts (1 molecule) of finely 
powdered crystallized cupric sulphate are added to the 
mass and the M'hole is intimately mixed, a rise in the tem- 
perature being carefully avoided. A uniform mass of a 
pale blue color is formed. Concentrated ammonia is then 
poured over the mass, in such quantity that for every mole- 
cule of cupro-hydrocellulose, 16 to 20 molecules of am- 
monia are used. Solution takes place immediately, and 
the greater portion of the sodium sulphate remains behind 
undissolved. 



CELLULOSE THREADS (cELLULOSE ARTIFICIAL SILk). 237 

The further working of the sohition of cellulose in cup- 
rammonium prepared according to this method is exactly 
the same as in Pauly's process previously described. 

PREPARATION OF CUPRAMMONIUM. 

Besides purified cotton, cuprammonium is the most im- 
portant product used in the manufacture of artificial silk 
according to Pauly's method, and its preparation consti- 
tutes an essential part of the entire manufacture. Com- 
mercial cupric sulphate or blue vitriol is, as a rule, used as 
the initial material, but in buying it, it must be taken into 
consideration that, as found in commerce, it is frequently 
very impure and contains a considerable quantity of ferric 
sulphate. A product almost chemically pure is only avail- 
able for our purpose. 

For the preparation of cuprammonium, cupric sulphate 
is dissolved in a sufficient quantity of water to form a sat- 
urated solution. As well water always contains a certain 
quantity of carbonates, which cause a separation of cupric 
carbonate, the solution is not clear, but more or less of a 
milky turbidity. This turbidity may, however, be readily 
removed by carefully adding to the fluid a small quantity 
of sulphuric acid and stirring thoroughly, the separated 
cupric carbonate being thereby redissolved, and the clear 
fluid then contains only cupric sulphate in solution. 

For the sake of precaution, the solution is filtered into 
another vessel, and after bringing it into brisk motion by 
means of a spatula, ammonia is added, a voluminous pale 
blue precipitate consisting of cupric hydroxide being formed. 
After each addition of ammonia, the fluid is thoroughly 
stirred and a small sample, previously filtered through 
paper, tested. If, on adding to the fluid in the test-tube a 
drop of ammonia, a precipitate of cupric hydroxide is 
formed, it is proof of all the copper in the fluid not having 
been separated ; and more ammonia has to be added. 

When a fresh sample remaing colorless, and after the 



238 CELLULOSE, AND CELLULOSE PRODUCTS. 

addition of a drop of ammonia, no noticeable changes are 
observed in it, it is proof of all the copper having been 
separated in the form of cupric hydroxide. Care must be 
taken not to add a larger quantity of ammonia than abso- 
lutely necessary for the precipitation of the cupric hydrox- 
ide, because by an excess of ammonia the cupric hydroxide 
just separated would be redissolved, and the fluid again 
acquire a deep, dark-blue coloration. 

When precipitation of the cupric hydroxide is complete, 
the contents of the vessel are allowed to stand quietly till 
the precipitate has settled to the bottom. The colorless 
supernatant fluid consisting of solution of ammonium sul- 
phate in water may be utilized as a fertilizer. 

By opening tap-holes placed at different heights in the 
wall of the precipitating tank, the solution of ammonium 
sulphate is drawn off as far as possible. Clear water is then 
poured over the precipitate and, after distributing the latter 
in the water by stirring, it is again allowed to settle. The 
supernatant clear fluid is again drawn off, and this washing 
of the precipitate is several times repeated till it may be sup- 
posed that all the ammonium sulphate has been removed. 
The pasty precipitate is then brought upon large cloths 
suspended by the corners, and allowed to remain upon them 
till no more water drains off; a certain quantity of water is 
also removed by squeezing. For the purpose of deter- 
mining exactly the quantity of water still contained in the 
mass, a weighed sample is dried at a moderate heat and 
then again weighed ; the loss in weight gives the quantity 
of water still contained in the mass and from it, is calculated 
the content of cupric hydroxide. Drying the sample used 
for this test should be effected at a temperature not exceed- 
ing 176° F., the cupric hydroxide being readily decom- 
posed by heating, to black cupric oxide and water. 

The cupric hydroxide is now brought into the apparatus 
in which it is to be converted into cuprammonium. This 
apparatus consists of a closed vat provided with a stirrer 



CELLULOSE THREADS (CELLULOSE ARTIFICIAL SILK). 239 

furnished with several paddles. While the stirrer is slowly 
revolving, the weighed quantity of cupric hydroxide is 
brought into the vat, and the ammonia is then allowed to 
run in. The cupric hydroxide dissolves readily to a clear, 
dark-blue fluid. 

When the stirrer has for some time been kept in motion, 
a small sample of the fluid is taken from the vat and allowed 
to stand quietly in a test-tube. If a precipitate is formed it 
is indicative of the total quantity of cupric hydroxide not 
having been dissolved, and more ammonia has to be added. 
Although an excess of ammonia does not hurt, it is a useless 
waste of material. The solution of cuprammonium is made 
of such a concentration that 1 liter (2.11 pints) contains be- 
tween 10 and 15 grammes (0.35 to 0.52 ozs.) of copper, the 
desired concentration being determined by means of an 
aerometer. Solutions with this content of copper are capa- 
ble of dissolving between 45 and 50 grammes (1.41 to 1.76 
ozs.) of cotton in 1 liter (2.11 pints) and the resulting solu- 
tions possess sufficient viscosity to yield, when decomposed 
by sulphuric acid, a thread of such tenacity as to allow of 
its being wound on the previously-mentioned glass roll. 

According to the process of E. Bronnert, M. Fremery and 
J, Urban, the preparation of solution of cuprammonium as 
solvent for cellulose is effected by filling a tall cylinder 
with copper-turnings and ammonia, and allowing cooled 
compressed air to ascend for ten hours in the cylinder. 
During this time the temperature of the fluid should not 
exceed 41° F., and for this reason the cylinder is furnished 
with a jacket in which cooled common-salt solution con- 
stantly circulates. At a higher temperature the dissolved 
cupric hydroxide would rapidly separate, and the content 
of copper in the fluid would not amount to over 2 to 2.5 
per cent. The solution thus obtained must also be kept at 
the same low temperature during the time required for the 
solution of the cellulose. 

The solubility of cellulose is claimed to be considerably 



240 CELLULOSE, AND CELLULOSE PRODUCTS. 

facilitated by previously subjecting it to thorough bleach- 
ing. For this purpose it is for 18 hours placed in a 15 per 
cent, chloride of lime solution, then washed and imme- 
diately brought into the cuprammonium. Cellulose thus 
treated dissolves to within 10 per cent. 

The mode of bleaching mentioned above is of great im- 
portance as regards the quality of the solution, cellulose 
more vigorously bleached yielding a solution which is not 
sufficiently gelatinous for the purpose of producing service- 
able textile threads. 

Cellulose also very readily soluble in cuprammonium is 
said to be obtained by treating it in the same manner as 
for the preparation of vegetable parchment : Immersion for 
a short time in quite concentrated sulphuric acid, and then 
washing with water for the comjDlete removal of the acid. 
For the production of threads from a solution of such cellu- 
lose in cuprammonium, the solution emerging from the 
spinners is simply precipitated with an acid, and the thread 
can be immediately wound on a roll, and dried at 104° F. 

RECOVERY OF THE COPPER. 

By the decomposition of the cuprammonium in the dilute 
sulphuric acid when the solution emerges from the spinners, 
the entire quantity of copper contained in the fluid remains 
behind in the sulphuric acid, the same being the case with 
the ammonia. Hence, in addition to cupric sulphate the 
fluid contains ammonium sulphate, and the copper has to 
be recovered. This may be effected in various ways, and 
depends on whether or not the ammonium sulphate dis- 
solved in the fluid is to be utilized. 

The simplest plan for the recovery of the copper is to 
treat the fluid with iron when it has been so far exhausted 
that it contains only a very small quantity of free sulphuric 
acid. By moving to and fro sheets of iron suspended in the 
fluid, copper in the form of a loose powder is separated, a 
corresponding quantity of iron being dissolved. The fluid 



CELLULOSE THREADS (CELLULOSE ARTIFICIAL SILK). 241 

remaining behind then contains, in addition to ammonium 
sulphate, ferrous sulphate (green vitriol) in solution. The 
separated copper only requires washing with water, and by 
treatment at a moderate heat with hj^drochloric acid can be 
redissolved. The solution which then contains cupric 
chloride may be immediately used for the preparation of 
cupric hydroxide. 

However, another plan may be adopted by which the 
ammonium sulphate may also be recovered and utilized by 
itself The dilute sulphuric acid in which the decomposi- 
tion of the cellulose solution is effected, is used until it con- 
tains but a very small quantity of sulphuric acid in a free 
state, when it is replaced by fresh acid. The fluid is then 
mixed with ammonia, the free sulphuric acid present being 
thereby converted into ammonium sulphate. By the addi- 
tion of still more ammonia the cupric hydroxide begins to 
separate, and by adding the correct quantity of ammonia 
all the copper present may be separated. The precipitated 
cupric hydroxide is again used for the preparation of solu- 
tion in ammonia, and theoretically, unlimited quantities of 
cellulose can be brought into solution with one and the 
same quantity of copper. The fluid freed from copper now 
contains ammonium sulphate in solution, which may be 
utilized by itself, the simplest plan being to employ it as a 
fertilizer, as the crystallization of such a comparatively 
small quantity of the salt would not be worth the trouble. 



After Chardonnet's process for the production of textile 
threads from nitro-cellulose solution became known, other 
patents were taken out which, however, are essentially only 
modifications, the same having also been the case with 
Pauly's method, but the principle remains intact. In all 
the new processes solutions of cellulose in cuprammonium 
are worked, the innovations consisting only in the subse- 
quent treatment of the thread obtained, which by this 
16 



242 CELLULOSE, AND CELLULOSE PRODUCTS. 

treatment, it is claimed, acquires greater lustre, fineness and 
tenacity. 

ARTIFICIAL SILK ACCORDING TO M. FREMEEY AND J. URBAN. 

The process patented by M. Fremery and J. Urban is 
said to yield threads of greater lustre and tenacity than 
those produced by Pauly's method. All the operations by 
this process up to the production of threads fit to be spun 
may be omitted, as they differ in nothing from Pauly's, the 
modification commencing only with the treatment of the 
thread when it emerges from the acid fluid. Without 
endeavoring to make them thinner by stretching, the 
threads while in a wet state are tightly wound on cylinders 
and allowed to dry upon them. The cylinders have quite 
a large diameter, so as to allow of a considerable quantity 
of thread being wound on them, and also of attaining 
greater tension during drying. 

The thread thus produced forms a soft, gelatinous mass 
very rich in water. By gradually yielding water to the air, 
its diameter, as well as its length, is decreased, but being 
tightly wound on the cylinder quite a considerable longi- 
tudinal strain ensues, whereby it gains in fineness and 
smoothness. , However, the thread is dried in the air only 
up to a certain degree, when the cylinder is brought into a 
room heated to 104° F., in which it remains until the 
thread is perfectly dry and can be wound on spools. 

Drying the thread in the above-mentioned manner— first 
up to a certain degree at the ordinary temperature, and then 
with the use of a higher temperature — is of great import- 
ance. If on coming from the spinning apparatus it were 
immediately exposed to the higher temperature it would, 
without tightening, dry to a brittle, lustreless product of 
porcelain-like appearance. 

According to observations of the patentees two phases 
may be distinctly observed in the drying process. In 
the beginning a considerable quantity of water evaporates 



CELLULOSE THREADS (CELLULOSE ARTIFICIAL SILK). 243 

in a comparatively short time. Evaporation then takes 
place very slowly, so that it may be supposed that a certain 
quantity of the water is chemically combined with the 
cellulose. This water may be rapidly brought to evapora- 
tion with the use of a higher temperature, but in this case 
the thread becomes brownish and loses lustre and tenacity. 

This drawback may be avoided by submerging the cyl- 
inder for a short time in water heated to between 158° 
and 212° F., or by allowing a current of steam to act upon 
it. This treatment is claimed to separate the chemically 
fixed water from the combination, and the process of drying 
is then effected in one-quarter the time which would other- 
wise be required. 

In addition to this innovation, which actually relates 
only to the mechanical manipulation of the cellulose thread, 
E. Bronnert, M. Fremery and J. Urban have introduced 
another modification which refers to the production of the 
thread itself. Instead of using for the decomposition of the 
cellulose solution in cuprammonium, a fluid which contains 
only 15 per cent, sulphuric acid, as is the case in Pauly's 
method, they employ a fluid which contains between 30 
and 05 per cent, sulphuric acid, a fluid with 50 per cent, 
sulphuric acid yielding, according to their statements, the 
best results. 

The thread passing from the spinner into such a fluid 
becomes immediately so firm and tenacious that the very 
disagreeable breaking of it does not happen, and conse- 
quently it can be allowed to emerge with great rapidity 
from the spinners and wound on the cylinder. The thread 
obtained in this manner is then further treated in the usual 
way, and yields a product which, as regards firmness, 
tenacity and lustre, answers all requirements. 

The effect of concentrated acid may be explained as fol- 
lows : The solution of cellulose in cuprammonium is de- 
composed the moment it passes into the sulphuric acid, 
hydro-cellulose being separated. However, by the great 



244 CELLULOSE, AND CELLULOSE PRODUCTS. 

affinity of concentrated sulphuric acid for water, this com- 
bination is immediately again decomposed and pure cellu- 
lose formed, which contracts quite considerably, thus form- 
ing a much firmer and more tenacious thread than is 
otherwise the case. It may, however, also be possible that 
by the action of the sulphuric acid, a thin layer of the cellu- 
lose is dissolved upon the surface of the thread and again 
separated, when the latter passes into less concentrated 
acid, the thread becoming thereby, so to say, varnished. 

If the chemical process actually runs its course in the 
above-described manner, it has a certain resemblance to 
that which takes place in the manufacture of vegetable 
parchment. By the immersion of the paper in concentrated 
acid, a contraction of the felted cellulose fibres is, on the 
one hand, effected, while on the other, a solution of the 
uppermost layer of cellulose immediately takes place. 
From this solution, when brought in contact with water, a 
substance is separated which, like a varnish, lies upon the 
surface of the paper, firmly cements together the individual 
fibres in the interior, and thus effects the great strength of 
vegetable parchment. 

ARTIFICIAL HORSE-HAIR. 

When thread resembling genuine silk in appearance, as 
closely as possible, is to be produced from cellulose solu- 
tion, a spinner with an aperture of a very slight diameter is 
used and the diameter of the thread, while the latter is still 
soft, is sought to be further reduced by stretching. Char- 
donnet, as previously mentioned, uses a spinner with an 
aperture only j-f^ millimeter in diameter, and by stretching 
the thread, while soft, its diameter may be considerably 
reduced. By the use of a spinner with a larger aperture, 
thread of a larger diameter may of course be obtained, 
though a certain limit should not be exceeded. When the 
thread exceeds a certain thickness, the decomposition of the 
combination and the separation of pure cellulose do not 



CELLULOSE THREADS (CELLULOSE ARTIFICIAL SILk). 245 

take place with such completeness as is required in order 
to obtain a uniform product. 

For the production of uniform threads of larger diameter, 
another method must therefore be adopted which is essenti- 
ally as follows : Spinners with apertures so large as is con- 
sistent with the preparation of a uniform thread are used. 
A number of such spinners are so placed that the threads 
emerging from them touch each other, just after they have 
been formed, while they are still beneath the level of the 
fluid. In this state — so to say, at the moment of formation 
— the threads unite, and there is no difficulty whatever, in 
thus obtaining threads, which as regards their diameter, 
are equal to horse-hair, and even surpass it. 

The threads thus obtained may be dyed any color de- 
sired, and are claimed to be available for all purposes for 
which horse-hair is at present used. In the textile industry, 
such threads might be utilized for the preparation of the warp 
for especially strong fabrics capable of great resistance, for 
instance, sail cloth. These threads are claimed to be especi- 
ally adapted for filaments for incandescent electric lamps, 
and may also be advantageously used for making the in- 
candescent body of gas light. 



XI. 

TEXTILE THREADS FROM VISCOSE (THREADS 
FROM LUSTRA-CELLULOSE.) 

Viscose solution when exposed to the air coagulates in a 
short time to a solid mass consisting of cellulose, and to 
obtain the latter in a perfectly pure state, it is only neces- 
sary to remove the alkali present by treatment with water. 
If viscose be allowed to emerge from tubes with a cylin- 
drical cross-section, threads suitable for textile fabrics are 
obtained. 

By reason of the great simplicity of the process of obtain- 
ing pure cellulose from viscose, much attention is very 
likely to be paid to the production of textile threads from 
this material. As shown by experiments on a small scale, 
such threads possess exactly the same properties as artificial 
silk prepared according to Pauly's method — because threads 
prepared from viscose consist of the same body as Pauly's 
silk, namely, cellulose, the only difference being in the 
manner of producing them. As shown by the experiments 
above-mentioned, thread prepared from viscose possesses a 
surprisingly high degree of lustre, and the term lustra- 
cellulose may properly be applied to it. 

Experiments made on a somewhat larger scale also 
yielded very favorable results, the thread exhibiting a 
magnificent silky lustre, and, therefore, viscose also would 
seem to have a great future for the manufacture of textile 
threads and fabrics. The cost of producing the threads will 
very likely not be any larger than in working according to 
Pauly's method, and is certainly far less than that of arti- 
ficial silk made by Chardonnet's process. 

(246) 



THREADS PROM VISCOSE (fROM LUSTRA-CELLULOSE). 247 

Threads made from viscose are distinguished by an ex- 
ceedingly small diameter, being in this respect at least 
equal to the finest quality of natural silk. In addition 
they possess great lustre and considerable strength, yield- 
ing, when woven, fabrics of great beauty which, without 
any further finishing, may be called glossy stuffs in the 
actual sense of the word. The viscose intended for the 
preparation of threads may be colored throughout the en- 
tire mass by simply adding coloring matter and thus, in a 
single operation, textile, and at the same time dyed, threads 
may be produced, which, after being thrown in the usual 
manner, may be woven into fabrics. With the use of vis- 
cose not dyed, pure white fabrics requiring no special 
bleaching or finishing are obtained. 

Since for the production of textile threads, materials are 
used which in themselves possess but little value, such as 
old purified cotton, or waste paper, or finally bleached cel- 
lulose from wood, the raw material is considerably cheaper 
than that used for the production of artificial silk from 
nitro-cellulose, and fabrics of lustra-cellulose are conse- 
quently cheaper than those of artificial silk, but withal of 
equal beauty. Together with Pauly's artificial silk, they 
will be able to compete triumphantly with artificial silk 
from nitro-cellulose. 

While artificial silk from nitro-cellulose is extraordinarily 
inflammable, and fabrics manufactured from it before being 
brought into commerce have to be subjected to denitration, 
tissues of lustra-cellulose are no more inflammable than 
ordinary linen or cotton fabrics, because they consist of 
pure cellulose. 

The factories engaged in the production of fine threads 
from viscose keep the apparatus used for the purpose a pro- 
found secret, but the construction of such an apparatus 
presents no difficulties, many portions of it corresponding 
with that generally used for the preparation of artificial 
silk threads. It is, however, of the utmost importance that 



248 CELLULOSE, AND CELLULOSE PRODUCTS. 

the viscose should be used in the form of a solution abso- 
lutely free from solid bodies. Many viscose solutions ap- 
pearing perfectly clear to the eye, may, nevertheless, contain 
entirely unchanged fibres of cellulose or nitro-cellulose, 
which have escaped the action of the carbon disulphide, they 
being invisible, because they possess quite the same power of 
refracting light as viscose solution itself. If such viscose 
were to be forced through the spinning apparatus, one after 
the other of the narrow apertures would soon be found to 
yield no thread whatever, and the apparatus could not be 
put in activity again even with the use of the highest 
pressure. 

In working on a small scale, the preparation of a perfectly 
clear viscose solution presents no difficulties whatever, but 
solution does not progress quite so smoothly when operating 
on a larger scale, the viscose on being brought in contact 
with water swelling up very rapidly, and the swelled-up 
mass preventing the access of water to the interior portions. 
Hence to effect solution in a short time a mechanical con- 
trivance has to be used by means of which the viscose is 
reduced and the formation of tough lumps prevented. A 
hollander is best suited for this purpose, as the thorough 
mixing of the solid mass with water can be effected by it in 
the most complete and rapid manner. 

The trough of the hollander is first filled with the quan- 
tity of water to be used for dissolving a fixed quantity of 
viscose, and the mechanism having been set in motion, the 
viscose to be dissolved is introduced in small portions. 
The whole is then worked till a uniform viscous mass is 
formed in which no dark spots or streaks can be noticed 
with the naked eye. 

However, the presence of undissolved particles can to a 
certainty be only prevented by filtering the finished viscose 
solution before introducing it into the spinning apparatus. 
Filtration of a fluid of such viscous nature as viscose causes 
considerable difficulties which may, however, be overcome 



THREADS FROM VISCOSE (fROM LUSTRA-CELLULOSE). 249 

by the use of an apparatus especially constructed for the 
purpose. As filtering material, it is best to use porous 
plates of cellulose. These plates are placed upon a metal 
plate perforated like a sieve, which forms the bottom of a 
solidly constructed cylinder. The latter is furnished with 
a lid fitting air-tight, and by means of a pipe is connected 
with a condensing air-pump. The cylinder having been 
filled with the viscose to be filtered, the lid is placed in 
position and the air-pump set to work, the pressure upon 
the fluid being only gradually increased to prevent the 
filter-plate from being torn asunder. When the pressure 
has attained a certain height, the viscose commences to 
trickle through the filter, and it is only necessary to keep 
up the same pressure in order to secure a uniform flow of 
the fluid. When the charge in the filter is almost ex- 
hausted, fresh viscose is introduced through a pipe on the 
side of the cylinder, the operation being thus continued so 
long as the filter remains effective. When, notwithstanding 
increased pressure, filtration is observed to become more 
and more sluggish, it is indicative of the pores of the filter 
being much obstructed, and the useless plate has to be 
replaced by a fresh one. For the purpose of dislodging the 
last remnants of viscose contained in the pores of the filter- 
plate, pure water is introduced into the cylinder until 
nothing but water runs off. 

This last remnant of viscose, which is quite dilute, is 
used in place of pure water for the preparation of fresh 
quantities of solution, and the cellulose plate which has 
become useless for filtration, is employed as raw material 
for the preparation of nitro-cellulose, nothing being thus 
wasted. 

It is advisable to make provision for the direct passage of 
the clear, filtered viscose from the filter into the reservoir 
of the spinning apparatus, to prevent it from being changed 
by contact with the air. 

The spinning apparatus consists in its main features of a 



250 CELLULOSE, AND CELLULOSE PRODUCTS. 

thick-walled metal vessel which can be closed air-tight, and 
can be connected with an air-compressing pump. In the 
bottom of this vessel sits the so-called spinning-plate, by 
means of which the formation of extremely thin jets of 
fluid is effected. In this spinning-plate are fixed a larger 
number of extremely narrow glass tubes conically enlarged 
above. The reservoir having been filled with the clear 
viscose solution, the air-compressing pump is set in motion, 
and the pressure increased to such an extent that the fluid 
is with a certain velocity forced from the narrow apertures. 

The same pressure must be maintained throughout the 
entire spinning operation, because only in this way can jets 
of fluid be made to emerge evenly from the spinning aper- 
tures, and this is of the greatest importance for the uni- 
formity of the threads. 

By allowing the threads emerging from the spinning 
apertures to hang down free, they stretch to a considerable 
extent by reason of the viscous nature of the viscose. The 
resulting threads are of a still smaller diameter than the 
original ones, and they break only b}' their own weight 
after having attained a certain length. It being desirable 
to produce threads of as small a diameter as possible, the 
length to which they may hang down free without danger 
of breaking has to be determined by experiments. How- 
ever, provision has then to be made for hardening them as 
rapidly as possible so that they may be reeled up. 

While viscose coagulates by itself in the air, too much 
time would in the case in question be required for the pur- 
pose, and it must therefore be sought to convert it in as 
short a time as possible into a solid body — viscoid. The 
transformation of viscose into viscoid is the more quickly 
effected the higher the temperature to which it is exposed, 
and the viscose threads after having been stretched to a 
certain length must be further treated according to this 
principle. 

This may be accomplished by the following arrangement: 



THREADS FROM VISCOSE (fROM LUSTRA-CELLULOSE). 251 

The reservoir containing the viscose to be spun is placed at 
a higher level, and the threads emerging from the spinning 
plate sink down free in a shaft-like space. On the bottom 
of this space, the coagulated threads are drawn through glass 
eyes and conducted to the reels on which they are wound. 
The latter contrivances closely resemble those used in silk- 
spinning establishments for reeling silk from the cocoons. 
For the purpose of converting the fluid viscose thread into 
the solid viscoid thread, a current of hot air ascends in the 
shaft through which the threads sink down. By this hot 
current of air the mass is solidified and the greater portion 
of the water at the same time evaporated. The tempera- 
ture and velocity of the current of air ascending in the shaft 
have to be accurately regulated and must be adapted to the 
rapidity with which the viscose is forced from the spinning 
apertures. The current of air must of course be so hot that 
the threads on reaching the lower end of the shaft are suffi- 
ciently firm and dry to allow of being reeled up. On the 
other hand, it must in ascending have already yielded so 
much heat, that the viscose emerging from the spinning 
apertures is not immediately coagulated, but retains suffi- 
cient viscosity to allow of the thread stretching to a certain 
extent in sinking down before reaching the layer of air in 
v/hich it is entirely coagulated. 

To bring about the co-operation of all the conditions by 
means of which threads of the proper quality can only be 
obtained, the same conditions must be adhered to in every 
particular. Thus it is b}^ no means immaterial whether 
there is a difference of a few degrees in the temperature of 
the viscose in the reservoir, its consistency — greater or less 
degree of viscosity — being influenced thereby, as well as the 
time the thread requires for coagulation. 

Eff'orts must, therefore, always be made to use viscose 
solution of the same temperature, and the apparatus fur- 
nishing the hot current of air should be so arranged that 
the temperature of the heated air can be exactly regulated. 



252 CELLULOSE, AND CELLULOSE PRODUCTS. 

this being accomplished without difficulty with the use of 
the so-called rib-heaters. The heater is enclosed in a box 
through which air is constantly forced by a small ventilator. 
By keeping the latter running uniforml}'^ and maintaining 
constantly the same expansion of steam, the air is heated in 
such a uniform manner that the temperature shows but 
exceedingly slight variations. If necessar}^, even the latter 
may be overcome by furnishing the box with a register by 
means of which the strength of the current of air may at 
will be increased or decreased, and the temperature in the 
shaft can thus be almost instantly raised or lowered. 

The viscose threads wound on the reels are of such a 
small diameter that they cannot be worked by themselves. 
A larger number of them — how man}' depends on the fine- 
ness of the fabric to be made — are therefore taken together, 
and converted by mechanical means into skeins which can 
be woven, being further worked exactly as any other yarn. 

PREPARATION OF TEXTILE THREADS FROM VISCOSE, ACCORD- 
ING TO STEARN. 

According to Ch. H. Steam's patented process, textile 
threads, as well as thin plates of viscoid, may be directly 
prepared by a simple method from viscose solution. The 
threads emerging from the spinning apparatus are immedi- 
ately allowed to drop into solution of ammonium chloride 
(sal ammoniac) in which they at once coagulate and can 
be directly reeled up or thrown. By fitting the bottom of 
the vessel containing the viscose solution, with a narrow slit, 
in place of the narrow apertures which furnish cylindrical 
threads, the viscose solution is obtained in the form of a 
thin, broad band, which also solidifies immediately in the 
ammonium chloride solution. The thin plates thus ob- 
tained may be used for writing and printing, as well as for 
photographic purposes, they being especially suitable for 
the preparation of the long, narrow strips which serve for 
taking pictures for the cinematograph. 



THREADS FROM VISCOSE (FROM LUSTRA-CELLULOSE). 253 

The cellulose threads prepared according to one or the 
other process have to be carefully washed, by being repeat- 
edly brought in contact with fresh quantities of water. To 
be quite sure of all the alkali having been entirely removed, 
the threads are finally passed through pure, highly diluted 
acetic acid, and then dried in the air. The acetic acid 
which is not fixed evaporates thereby, and the threads then 
cannot contain any free alkali. 

Millar's artificial silk (gelatine silk). 

While in all the previously-described methods for the 
preparation of textile threads either nitro-cellulose or cellu- 
lose solutions form the basis-material, in Millar's process, 
as well as in a very similar one, published by Hummel, 
glue is used as the initial raw material. By reason of the 
^reat viscosity of glue solution it may be made into threads, 
and the glue contained in them can by suitable treatment 
be converted into an insoluble combination. 

The textile threads thus produced have, however, not 
stood the test as compared with other artificial threads, and 
we may here confine ourselves to giving merely the outlines 
of the mode of manufacturing them. 

According to Millar's process, 2 lbs. of glue of finest 
quality (gelatine) are broken up in small pieces and allowed 
for one hour to stand quietl}'^ together with 4 lbs. of cold 
water. The mass is then for two hours heated to 120.2° 
F., the result being a very thick solution in water which, 
when forced through narrow tubes, can be drawn into 
threads. The latter are conducted into a room filled with 
vapors of formaldehyde whereby the glue is rendered in- 
soluble. 

A modification of Millar's process, consists in adding to 
the glue solution a quantity ofpotassium dichromate equal 
to about 2 per cent, of the weight of glue used. The 
threads spun from the solution are exposed to the light 
whereby the glue is also converted into a combination in- 
soluble in water. 



254 CELLULOSE, AND CELLULOSE PRODUCTS. 

While the threads obtained by either one of these pro- 
cesses, present quite a nice appearance, they do not possess 
sufficient flexibility and elasticity to be utilized for tissues. 
If a thread be once or twice bent, and then placed under 
the microscope, the bent places will be seen full of cracks, 
and by repeated bending the thread would break. A 
further disadvantage is that the threads swell very much 
in moist air. 

By drawing gelatine threads after they have acquired a 
certain degree of solidity through solution of an aluminium 
salt, or tannin solution, their brittleness, as well as their 
tendency to swell up in moist air, is somewhat reduced, 
but the resulting product cannot bear comparison, as re- 
gards beauty and strength, with cellulose threads, and there 
is very likely no prospect of the production of gelatine 
threads which might be available for practical purposes. 

GENERAL PROPERTIES OF TEXTILE THREADS PRODUCED BY 
ARTIFICIAL MEANS. 

The textile threads produced by one or the other of the 
processes previously described, possess properties which in 
many respects differ essentially from those of genuine silk 
or of cellulose derived from plants, and, in dyeing as well 
as in weaving, they have to be differently treated. 

Threads from nitro-cellulose, as well as from pure cellu- 
lose, possess much greater lustre than natural silk, and, in 
addition to this high lustre, are stiffer and more elastic, 
these properties being of great advantage in working them. 

However, on the other hand, the manipulation of arti- 
ficial silk is rendered very difficult by the fact, that, when 
brought in contact with water, the threads lose the greater 
portion of their tenacity, the latter, as shown by direct 
measurements, being reduced to ^ and even to y^ of the dry 
thread. The cause of this phenomenon is that the threads, 
on coming in contact with water, swell up very much, 
whereby the coherence of the separate particles is to a great 
extent broken up. 



THREADS FROM VISCOSE (PROM LUSTRA-CELLULOSE). 255 

In dyeing threads of artificial silk, the above-mentioned 
facts have to be taken into consideration, and moderately 
warm dye-baths of a temperature not exceeding 140° F., 
should only be used. Great care must also be exercised in 
handling the skeins in the dye-bath to avoid breaking off a 
large portion of the threads. By reason of the threads 
swelling very much, they take the dye more rapidly than 
is the case with natural silk, and for delicate shades very 
dilute dye solutions have to be used, there being otherwise 
danger of over-dyeing. 

When dyeing is finished, the skeins or fabrics must by 
no means be wrung out as may be done with natural tex- 
tile fabrics, but must be freed from adhering dye-fluid by 
whirling in a centrifugal, further washing with water being 
also effected with the latter apparatus. 

As regards the further properties of artificial textile 
threads, the microscope furnishes an excellent means for 
their examination, and with its assistance genuine silk can 
immediately be distinguished from the artificial material by 
the form of the latter, which in itself proves it to be an arti- 
ficial product. While natural silk always appears as a 
smooth cylinder of uniform thickness with only a few cross 
stripes, the artificial thread never possesses such uniformity, 
being considerably thicker in some places than in others. 
It is, as a rule, not perfectly round, but more or less flat- 
tened, this being especially the case with Chardonnet silk, 
while Pauly's is much more uniform, its shape approaching 
more closely that of a cylinder. 

The difference between natural and artiflcial silks be- 
comes especially noticeable under the microscope on moist- 
ening the sample with water. While natural silk does not 
swell up to a noticeable extent by remaining even for a 
long time in contact with water, the artiflcial product im- 
mediately commences to swell up and acquires a width J to J 
greater than when dr3^ 

The compilation given below is based upon micrometrical 



256 CELLULOSE, AND CELLULOSE PRODUCTS. 

measurements, and shows the diameters of various kinds of 
natural silk in a swollen state. To obtain the diameters of 
the threads in a dry state, deduct i to J from the figures 
given : 

Mean. Maximum. 

Chardonnet silk 45 to 60 100 

Fisraes silk 40 to 80 120 

Lehner silk 60 to 90 135 

Pauly silk 40 to 50 75 

Gelatine silk 60 to 80 85 

Genuine silk 9 to 15 20 

In the optical way, artificial silk, wdth the exception of 
threads prepared from gelatine, can also be immediately 
recognized by its double refraction of light. Genuine silk, 
to be sure, possesses the same pov/er of refracting light but, 
with some practice, the diff'erence between it apd the arti- 
ficial product can be readily discovered. By examining in 
the polarizing instrument a thread of genuine silk in such 
a way as to observe diff'erent portions of it, the same color 
phenomena will always appear. However, in consequence 
■of its irregularity, such is not the case with artificial silk, 
the thicker places showing entirely diff'erent colors from the 
thin ones. On the places where the narrow side of the 
flattened thread is before the eye, the color, as a rule, is 
green or blue. 

The richest color phenomena are observed in Lehner's 
silk, the separate threads showing colored longitudinal 
stripes which are yellow, red, green, or steel-blue, a proof of 
great variations in their dimensions. 

The tenacity of the threads is, as a matter of course, a 
very important property of silk, the manner of working it 
not only depending on it, but also the durability of the 
products manufactured from it. 

Thus far no artificial silk possessing more than one^ialf 
the tenacity of genuine silk has been produced. The com- 



THREADS FROM VISCOSE (FROM LUSTRA-CELLULOSE). 257 

pilation given below shows the tenacity of different varieties 
of silk : 

Genuine silk 100 

Chardonnet silk 44 

Vivier silk 29 

Pauly silk 45 to 50 

Lehner silk 68 

Dr. Hassack has made numerous investigations as regards 
the moisture and hygroscopicity of artificial silks, as well as 
the products themselves in general, and from his voluminous 
work on this subject, the most important data are here given. 

The results of the determination of moisture calculated 
to 100 grammes (3.52 ozs.) dry substance, were as follows : 

Content of moisture 
in per cent. 

Indian raw silk 8.71 

Pr^s de Vaux silk 11,11 

Fismes silk 10.92 

Walston silk 11.32 

Lehner silk from Glattbrugg 11.45 

Dr. Pauly' s cellulose-silk 9.20 

Gelatine silk 13.98 

The hygroscopicity of the silks was determined by allow- 
ing the dried and weighed samples to remain for 24 hours 
in air completely saturated with steam, when they were 
again weighed. The absorption of water in per cent, was 
us follows : 

Italian raw silk 20.11 

Pr^s de Vaux silk 27.46 

Fismes silk 27.12 

Walston silk 28.94 

Lehner silk from Glattbrugg 26.45 

Cellulose silk 23.08 

Gelatine silk 45.56 

The specific gravity of artificial silks approaches quite 
•closely that of genuine silk, gelatine silk almost correspond- 
17 



258 CELLULOSE, AND CELLULOSE PRODUCTS. 

ing with it, while that of the other is 10 to 11 per cent, 
greater. 

ELASTICITY AND TENACITY OF ARTIFICIAL SILK. 

These investigations, of great importance for the utiliza- 
tion of artificial textile fibres, were made by Dr. Hassack in 
the following manner : 

Pieces of thread of genuine silk and of the silk to be 
tested were placed in the tearing apparatus in such a way, 
that a free thread 3.93 inches long was lying between the 
two binding screws, and the length of the thread just placed 
in the apparatus without being stretched was accurately 
measured. The tension was then increased till the thread 
broke, and the length of the piece of thread at the moment 
of breaking was again measured, the figures showing the 
load at the moment of breaking, as indicated by the instru- 
ment, being at the same time noted. After every test one 
of the pieces of thread was placed under the microscope, and 
the number of fibres composing it were counted, so as to be 
able to determine the separate factors for a single spinning 
fibre. 

To avoid errors every determination was five or six 
times repeated, and the arithmetical mean of the results 
taken. The claim of being correct may therefore be made 
for the figures given below. The results were for : 

Genuine silk (Piemont-Organtin) 21.6 per cent. 

Chardonnet silk from Pres de Vaux 8.0 " 

Collodion silk from Fismes 11.6 " 

Collodion silk from Walston 7.9 " 

Lehner silk 7.5 

Pauly's cellulose silk 12.5 " 

Gelatine silk 3.8 

The mean results obtained by the breaking tests are 
given in the table below. In order to be able to compare 
them with those obtained with genuine silk, the figures 
referring to the latter have been added. The silk tested 



"threads from viscose (from lustra-cellulose). 259 

was of medium tenacity and the titer 22 to 24 den.* In 
the last column of the table the relative tearing resistance 
of the samples examined, is calculated to the unit titer of 
100 den. 



Variety. 




Titer in 
den. 


Relative 

breaking 

resistance. 


Calculated 

to titer of 

100 den. 


Expressed in 

per cent. 

Genuine silk 

= 100. 




g- 


g- 


per cent. 


Genuine silk . 
Chardonnet sil 
Fismes silk . 
Walston silk . 
Lehner silk . 
Cellulose silk 
Gelatine silk . 


i . 


22 to 24 
about 80 
about 100 
about 120 
110 to 135 
about 120 
about 100 


57.5 

74.2 

71.7 

15L4 

171.8 

197.6 

63.0 


250 

92 

72 

125 

141 

163 

63 


100 
37 
28 
50 
56 
66 
25 



BEHAVIOR OF ARTIFICIAL SILK IN A CHEMICAL RESPECT. 

Chemically artificial silks differ very essentially from 
the genuine product, but with the sole exception of 
threads prepared from gelatine, the}^ quite agree one with 
the other as regards their behavior towards chemical re- 
agents, j The examination of artificial silk in a chemical 
respect is generally made with the assistance of the micro- 
scope, it being possible with this instrument immediately 
to distinguish artificial silk alongside of genuine silk or 
another fibre in a tissue. 

The principal difference, as regards their chemical be- 
havior, between the different kinds of artificial silk known 
at present, depends on the mode of their preparation, and 



* 1 den. (1 denier) = 0,10 g. per 1000 ni. length of thread. 



260 CELLULOSE, AND CELLULOSE PRODUCTS. 

the difference between silk consisting of pure cellulose — 
Pauly's silk and viscose silk — and that made from nitro- 
cellulose has above all to be determined. 

When a sample of the threads under the microscope is 
touched with solution of diphenylamine in concentrated 
sulphuric acid, threads prepared from nitro-cellulose are 
immediatel}'^ colored intensely blue, because none of these 
silks are ever entirely denitrated. This reaction is so dis- 
tinct as to be plainly perceptible even with artificial silk 
which has been dyed. Artificial silk of pure cellulose is 
entirely indifferent towards this reagent. 

When artificial silk, swelled up by having lain in water, 
is moistened under the microscope with absolute alcohol or 
concentrated glycerin, it rapidly regains its original volume 
in consequence of the absorption of water from it. 

Swelled-up threads of artificial silk, especially such as 
have, in addition, been boiled in water, can be readily 
mashed with the object-glass and broken, this being espe- 
cially the case with gelatine silk. 

Artificial silk when touched with concentrated sulphuric 
acid is dissolved, solution taking place quite rapidly with 
nitro-cellulose silk, while threads of pure cellulose first swell 
up very much, then constantly become thinner, and finally 
disappear entirely. In the commencement of the action of 
the sulphuric acid, cellulose silk exhibits plainly perceptible 
longitudinal streaks. Gelatine threads at first shrink up 
very much by the action of sulphuric acid, then swell up, 
though not to a great extent, and dissolve only when strongly 
heated with the sulphuric acid. By concentrated hydro- 
chloric acid, fibrils are gradually detached from nitro-cellu- 
lose silk ; the threads when boiled with it show longitudinal 
and cross rents, and can be broken into small sharp-cornered 
pieces when pressed with the object-glass. Gelatine silk is 
rapidly attacked by hydrochloric acid and in a short time 
dissolved by it. By acetic acid, cellulose silk, as well as 
collodion silk, is swelled up, while gelatine silk is completely 
dissolved by it. 



THREADS PROM VISCOSE (FROM LUSTRA-CELLULOSE). 261 

All kinds of artificial silk are in a short time dissolved at 
the ordinary temperature by half-saturated chromic acid 
solution, the fluid acquiring a brown color. Genuine silk, 
to be sure, is also dissolved by this reagent, but consider- 
ably more time is required than for artificial silk. Vege- 
table fibres not being attacked by chromic acid, it can in 
this manner be at once determined whether only the woof 
of a piece of tissue of silk-like appearance consists of arti- 
ficial silk (or genuine silk), and the warp of threads of 
vegetable origin. 

• Concentrated soda or potash lye causes cellulose silk, as 
well as collodion silk, to swell up very much without solu- 
tion being effected even after continued boiling. The fluid, 
however, is colored yellow. Genuine silk, when treated 
with a concentrated alkaline solution, dissolves at the boil- 
ing point, the solution, however, remaining colorless. 
Gelatine silk shrinks up very much, and then passes very 
rapidly into solution. 

Genuine silk, collodion silk and cellulose silk, when 
treated with cuprammonium solution, swell np very much 
in the fluid, and then pass gradually into solution. With 
threads consisting of nitro-cellulose, the small bubbles 
almost always occurring in artificial silk are plainly visible. 
Cellulose silk swells up very slowly, and the longitudinal 
and cross streaks are more distinctly recognized than is the 
case in water ; finally, complete solution takes place. Gel- 
atine silk is not dissolved by cuprammonium, but is colored 
pale violet. 

Cellulose and nitro-cellulose silks may also be plainly 
distinguished from genuine silk by treating the threads with 
alkaline cupric oxide (glycerin) solution. Genuine silk is 
immediately dissolved when heated together with this fluid 
to 176° F. Genuine Tussah silk requires somewhat longer 
for solution — about one minute — gelatine silk acting in the 
same manner. Nitro-cellulose silk and pure cellulose silk 
are entirely indiff'erent towards this reagent. 



262 CELLULOSE, AND CELLULOSE PRODUCTS. 

Solution of iodine in. potassium iodide solution colors all 
varieties of artificial silk intensely red to brown, the color- 
ation, however, disappearing by subsequent treatment with 
water, though nitro-cellulose silk exhibits thereby a transient 
blue-gray color. With the use of iodine solution and dilute 
sulphuric acid, genuine silk is colored yellow by the fluid ; 
nitro-cellulose silk acquires a deep blue color shading into 
violet, while cellulose is colored pure blue. Gelatine silk 
is colored yellow-brown to red-brown. 

Iodine zinc chloride solution colors genuine silk yellow, 
and collodion silk blue-violet, while cellulose silk only 
acquires a gray-blue to gray-violet color. Gelatine silk is 
colored yellow like genuine silk, but falls immediately to 
pieces, while the structure of genuine silk remains intact. 

Cellulose silk burns in somewhat the same manner as 
pure cotton, and leaves scarcely any residue, while collodion 
silk leaves behind a small quantity of pure white or gray 
ash. Gelatine silk when burning gives off vapors of the 
same disagreeable odor as those evolved by burning glue. 



XII. 

CELLULOID. 

This peculiar substance was first prepared, in 1869, by- 
Hyatt, of Newark, New Jersey, and the original process 
used by him is said to be at present employed — though 
probably with many modifications — in many factories. 

Celluloid is distinguished by various properties which 
render it available for many industrial purposes, and there 
is scarcely another substance so well adapted for the imita- 
tion of various bodies ; such as tortoise shell, ivory, coral, 
etc. These imitations can be made in such perfection that, 
judging solely by their appearance, they frequently cannot 
be distinguished from the genuine bodies. In addition to 
these applications, which relate more or less to the produc- 
tion of fancy articles, celluloid has found its way into sev- 
eral industries. It forms at present a ver}' important 
material in the manufacture of sets of artificial teeth, and it 
is also frequently made use of for the production of cliches. 

Although the physical properties of celluloid are ac- 
curately known, its chemical nature is thus far not under- 
stood, it being uncertain whether it is a chemical combina- 
tion at all, or only a mixture of certain bodies possessing 
the peculiar physical properties on which depends its great 
applicability. Hence, from the present state of our knowl- 
edge, celluloid has to be considered an intimate mixture of 
the substances used in its preparation. However, it may 
here be remarked that the nitro-cellulose contained in cel- 
luloid, strange to say, loses entirely its explosive power, and 
is simply inflammable. 

Celluloid consists essentially of an intimate mixture of 

(263) 



264 CELLULOSE, AND CELLULOSE PRODUCTS. 

soluble nitro-cellulose (collodion gun-cotton) with camphor. 
As the mixture permanently retains the penetrating odor 
of camphor, the use of the product for various purposes is 
made impossible, and it has been sought to replace the 
camphor by substances entirely odorless or of a less intense 
odor. This object has been partially attained, and celluloid 
masses entirely free from odor are at present prepared. 

Several methods for the preparation of celluloid are 
known, and they may be designated as dry and wet pro- 
cesses. According to the dry process which was used by 
Hyatt, the substances constituting the mass are simply 
combined by mechanical means — kneading, rolling and 
pressing. In the wet process, fluids capable of dissolving 
collodion-cotton as well as camphor are used. When the 
solutions have been prepared, the solvent is allowed to 
evaporate, whereby the celluloid remains behind, and is 
then further worked by mechanical means. 

As regards the value of the separate methods, it may be 
said, that they all yield a product of equal quality and it is 
only a question of which is the cheapest. The purely 
mechanical process has the undisputable drawback of a 
number of quite complicated machines being required, and 
working the masses takes considerable time and power. 

The process, in which the substances to be combined are 
used in the form of solutions, requires but a small expendi- 
ture of power ; however, a very large portion of the solvent 
is unavoidably lost by evaporation. 

With the use of suitable auxiliary contrivances, the loss 
of solvent by evaporation may be considerably reduced by 
condensing the greater portion of the vapors to fluid, as will 
be explained below, and for this reason the wet process 
would appear to deserve the preference. 

Although various methods for the preparation of celluloid 
have, in the course of time, become known, most of them 
have proved to be only immaterial modifications of the main 
process. The manufacturers very likely introduced these 



CELLULOID, 265 

modifications simply for the purpose of not coming in con- 
flict with the owners of the patents for the fabrication of 
celluloid according to one of the chief processes. 

With regard to the methods used for the manufacture of 
celluloid, we may distinguish : 

1. The dry method or HyaWs process. In this method the 
wet soluble nitro-cellulose is by rolling combined with 
camphor to a homogeneous mass. 

2. The wet methods. According to the solvent employed^ 
several methods may be distinguished, namely : 

a. Magnuses process. This is based upon dissolving col- 
lodion-cotton and camphor in ether, and evaporating the 
ether by heating the solution. 

b. Process employed by the factory at Stains, near Paris. 
This is based upon the fact that collodion-cotton and 'cam- 
phor are also soluble in methyl alcohol, and that the latter 
may therefore be used to effect solution. By both of these 
wet processes, celluloid is obtained which in itself is very 
homogeneous and requires mechanical manipulation only 
for a short time to render it fit for further working. 

PREPARATION OF THE COLLODION-COTTON. 

The principal requisite for the manufacture of celluloid 
is the use of a nitro-cellulose completely soluble in the 
known solvent. As regards the preparation of such a pro- 
duct, the reader is referred to what has been said in this 
respect in describing the manufacture of artificial silk ac- 
cording to Chardonnet's method. It may be repeated that 
in working according to one of the wet processes, the use of 
a perfectly soluble product is of the utmost importance, , 

When working with freshly prepared collodion cotton, its 
complete solubility has to be ascertained by treating a small 
sample with the solvent. If the test shows the collodion 
cotton not to be completely soluble, it may nevertheless be 
used for the manufacture of celluloid, but the solution must 
by all means be filtered, though filtration need not be so 



266 CELLULOSE, AND CELLULOSE PRODUCTS. 

thorough as when the collodion is to be used for the manu- 
facture of threads. For the purpose of filtration it suffices 
to force the solution under slight pressure through a layer 
of cellulose, 0.59 to 0.78 inch thick, in order to obtain a 
fluid in which the camphor may be dissolved. 

According to the original statements by Hyatt, collodion- 
cotton suitable for the purpose of preparing celluloid can 
only be obtained by using for nitration an extraordinarily 
fine quality of paper consisting of pure cellulose. Hyatt is 
said to have employed for this purpose the finest quality of 
tissue-paper torn into small pieces by a special machine. 
These pieces were then treated with nitrating fluid. 

It will be readily understood that with the use of such 
an expensive raw material as a fine quality of tissue-paper, 
the cost of producing collodion-cotton would be very much 
increased, and it would be impossible to furnish celluloid 
articles at the low price at which they are at present 
brought into commerce. It has, however, been shown that 
for the manufacture of celluloid, collodion-cotton prepared 
from any kind of cellulose may be used, provided the latter 
has been subjected to sufficient purification. 

PREPARATION OF CELLULOID ACCORDING TO HYATT. 

The collodion-cotton, carefully freed from acid, is as far as 
possible dehydrated by the use of a powerful press, then 
reduced, and completely dried. It is not stated how drying 
is to be effected, but the process described for the prepara- 
tion of nitro-cellulose may be employed. The dry collodion- 
cotton is carefully triturated, mixed with camphor and 
subjected to further treatment by mechanical means. This 
account, as will be seen, gives a very meagre description of 
the manufacture of celluloid, no data regarding the manner 
of mixing the collodion-cotton with the camphor being fur- 
nished, nor is any reference made as to the proportions in 
which the materials are to be mixed. A somewhat better 
insight into Hyatt's process is afforded by the following 
description : 



CELLULOID. 267 

The collodion-cotton previously carefully washed is 
ground fine in a hoUander, and converted into quite a solid 
cake by removing the water by pressure. This cake is 
again reduced and mixed, under water, with camphor. 
Mixture being complete, the mass is kneaded and rolled by 
mechanical means. The object of this manipulation is 
probablj'' to bring the particles of collodion-cotton and 
camphor into still more intimate contact, and, in addition, 
to cause evaporation of a large portion of the water con- 
tained in the mass. The latter having now become quite 
solid, is subjected to a very high pressure whereby more 
water is removed, and the combination of the nitro-cellulose 
with the camphor completed. 

The mass is contained in a jacketed cylinder, the bottom 
of which is formed by the piston of a hydraulic press. 
While the latter is at work, steam is introduced into the 
space between the jacket and the cylinder, and the temper- 
ature is gradually raised till the contents of the cylinder 
are heated to 266° F. Although at this temperature cam- 
phor has already great tendency towards vaporization, b}'^ 
reason of the state of fine division in which it is, in conse- 
quence of the previous operation, the vapors evolved can 
only spread to the particles of collodion-cotton lying next 
to them. Hence, this treatment at a higher temperature 
and at a high pressure can probably be only viewed in the 
light of making the mass finally and completely homo- 
geneous. 

With the use of a mixture consisting only of collodion- 
cotton and camphor, the cylinder, when the above-mentioned 
temperature has been reached, contains a colorless mass. In 
the hot state, this mass possesses a very high degree of plas- 
ticity, but on cooling to the ordinary temperature, becomes 
firm and quite hard. In the state in which it comes from the 
hydraulic press it can be rolled out to plates of any thick- 
ness, or pressed in moulds, being left in the latter till 
cooled to the ordinary temperature. 



268 CELLULOSE, AND CELLULOSE PRODUCTS. 

Celluloid being a substance which can be dyed any de- 
sired color, as well as mixed with pulverulent materials, 
articles differing very much in appearance may be made 
from it. The admixture of the foreign bodies may be 
effected previous to bringing the mass into the hot press, or 
when it is taken from the latter. In the latter case, the 
celluloid is rolled out into thin plates upon which the pul- 
verulent substances are scattered, and rolling is repeated 
until a perfectly homogeneous mass is obtained. 

Regarding the quantities of the two fundamental con- 
stituents of celluloid, it may be stated that for every two 
parts of collodion-cotton one part of camphor is said to be 
used. 

PREPARATION OF CELLULOID ACCORDING TO TRIBOUILLET 
AND BESANCELE. 

According to this method, which, in a certain sense, ap- 
pears to be an improvement on Hyatt's process, 100 parts of 
collodion-cotton are very intimately mixed with 42 to 50 
parts of camphor.* The mass is then wrapped in very strong 
press-cloths, and brought into a hot-press, very similar in 
construction to that used in candle factories for pressing oleic 
acid from crude acid cakes. The masses to be pressed lie 
between hollow iron prisms heated by steam, and by means 
of a hj'draulic press the whole is pressed together to the 
same extent as the press-cakes become thinner. The press 
is enclosed in a box, and the latter is connected by means 
of a pipe with a cooled space in which the vapors escaping 
from the hot pressed mass are condensed. In pressing the 
mixture of collodion-cotton and camphor, the escaping 
vapors can only consist of water and camphor, and the 
object of this arrangement seems to be to recover the cam- 
phor present in excess. 

* Although it is not thus stated, mixture is probabl)' effected in a wet state 
in a hollander. 



CELLULOID. 269 

After remaining for several hours in the press, the cakes 
are brought into a box upon the bottom of which stands a 
vessel containing a substance having great affinity for 
water — calcium chloride or sulphuric acid — and the air in 
the vessel is then exhausted. The mass is thus completely 
dried, and the preparation of the celluloid finished. Ac- 
cording to the present state of the industry, all the processes 
for the production of celluloid by purely mechanical means 
may be designated as obsolete, and, in all probability, they 
have generally been abandoned. Although it is a fact that 
by the presence of the camphor the nitro-cellulose is de- 
prived of its explosive power, it cannot be denied that such 
is the case only when the mixture is sufficiently intimate. 
However, such an intimate mixture is only effected towards 
the final stages of the manufacturing process, and up to 
that period the operation is by no means free from danger, if 
■care is not taken that the mass up to the time of hot-press- 
ing contains enough water to render explosion impossible. 

PREPARATION OF CELLULOID WITH ALCOHOLIC CAMPHOR 
SOLUTION. 

This process yields good results, and is said to possess the 
great advantage of all danger of explosion being excluded 
— which, however, may be doubted. The collodion-cotton 
is prepared by grinding, and is then freed as far as possible 
from water, when solution of camphor in strong alcohol is 
poured over it, the solution being brought in contact with 
all portions of the collodion-cotton by vigorous manipula- 
tion of the mass. 

The mass is then heated in a closed vessel under 
pressure. Alcohol boiling at a temperature far below the 
boiling point of water, it will be impossible to reach in such 
a vessel a temperature of 266° F., at which the formation 
of celluloid is said to take place. Heating should probably 
not be carried beyond a point at which complete solution 
•of the collodion-cotton in the alcoholic camphor solution is 



270 CELLULOSE, AND CELLULOSE PRODUCTS. 

effected. While collodion-cotton does not dissolve in alco- 
hol at the ordinary pressure, solution is effected by heating 
it together with alcohol under a certain pressure. 

When solution is complete, the mass is allowed to remain 
in the closed vessel until cooled to the ordinary tempera- 
ture. It forms a gelatinous substance consisting of celluloid 
saturated with alcohol and water. For the removal of the 
latter, heat cannot be applied as otherwise the surface which 
solidifies first would be full of bubbles caused b}'^ the vapors 
being unable to escape through the viscous mass. Hence, 
in order to obtain a uniform product free from bubbles, the 
soft celluloid mass will have to be cut up into thin slices, 
and the latter dried in a warm room. Drying requires 
quite a long time, and all the alcohol used is lost. When 
a piece not thoroughly dry is tested with a knife, the out- 
side will be found quite solid while inside it is of a lard- 
aceous nature. By immersing the dry pieces in hot water, 
they can be made soft and plastic, and by rolling readily 
combined to a homogeneous mass. 

PREPARATION OP CELLULOID ACCORDING TO MAGNUS. 

The process introduced by Magnus, of Berlin, for the pre- 
paration of celluloid is perhaps the most rational one of all 
the wet methods, because with the exercise of sufficient care 
all danger of explosion or fire is excluded. 

The description of Magnus's process, which has become 
public, is also very meagre, and it may be seen at the first 
glance that it contains only the principle of the entire pro- 
cess, but that its technical execution will probably have to 
be effected in a less simple manner. 

According to law, collodion-cotton as brought into com- 
merce must contain at least 25 per cent, of water, the possi- 
bility of explosion being only excluded under these condi- 
tions. Now, it has been stated, that in the Magnus factory, 
the wet, compressed collodion- cotton is separated and dried 
upon hot iron plates(!). An explosion of collodion-cotton 
thus treated could in all probability scarcely be avoided. 



CELLULOID. 271 

The mode of preparing the solution of dry collodion- 
cotton is as follows : Over 50 parts by weight of collodion- 
cotton is poured a mixture of 100 parts by weight of ether 
and 5 parts b}^ volume of alcohol of 0.728 specific gravity, 
28 parts by weight of camphor having been previously dis- 
solved in this mixture. Stone-ware pots covered with a 
loaded rubber plate are used for dissolving purposes. The 
mass is from time to time stirred till solution is complete 
and the pots contain a gelatinous mass. It is further stated 
that this mass becomes plastic after some time by manipu- 
lation between rolls, and that plates may be prepared from 
it which are kept till, by the evaporation of the greater por- 
tion of the ether, they have become hard enough to be 
pressed, the latter operation being effected in hot presses, 
and the quality of the celluloid is said to be the better, the 
more sharply the plates are pressed. 



According to another process which differs but little from 
the one described above, in place of ether, methyl alcohol 
in which the required quantity of camphor has been dis- 
solved is used as a solvent for the collodion-cotton. 

PREPARATION OP CELLULOID WITH RECOVERY OF THE 
SOLVENT. 

It must appear strange to any one conversant with chem- 
ical principles, how incomplete and, in certain respects, very 
singular, are the descriptions given above for the preparation 
of celluloid. It is, therefore, considered advisable to give 
here a description of a process which can be practically ap- 
plied, it being without danger and allowing of the recovery 
of the quite expensive solvents. 

With reference to the basis-material of the entire celluloid 
manufacture, namely, collodion-cotton, it may be said that, 
while it could probably be obtained from different manu- 
facturers of chemical products, it would be preferable to 
prepare it in the celluloid plant itself, because by this means 



''Ill CELLULOSE, AND CELLULOSE PRODUCTS. 

a product would be obtained which, as regards complete solu- 
bility, answers all demands. In a larger plant producing 
annually large quantities of celluloid articles, the prepara- 
tion of collodion-cotton in the plant itself would also appear 
-advisable from an economical standpoint. 

In describing the manufacture of artificial silk according 
to Chardonnet's method, attention has been drawn to the 
great care bestowed upon the production of nitro-cellulose 
which is completely soluble, and collodion-cotton possessing 
this property being also required for the manufacture of 
celluloid, the reader is referred to the process used by Char- 
donnet. AVhen a freshly-prepared quantity of collodion- 
cotton is to be worked, it is, in all cases, advisable to test a 
sample of it as to its solubility. For this purpose a small 
quantity of the collodion-cotton is thoroughly dried. One 
gramme (15.43 grains) of the dry mass is brought into a 
large test-tube and 200 cubic centimeters (12.2 cubic inches) 
of ether are poured over it. Solution is hastened by con- 
tinued shaking, and the test-tube is then placed perpen- 
dicularly in a place protected from shocks. 

In the course of 24 hours, the contents of the test-tube 
should form a clear, transparent fluid, which is a proof of 
the entire quantity of collodion-cotton having been dis- 
solved in the ether. If an opalescent layer appears on the 
bottom of the test-tube, it consists of nitro-cellulose swollen 
up but not dissolved. The quantity of this can be readily 
determined by quickly filtering the fluid, washing the 
residue remaining upon the filter with ether, drying and 
weighing it. By deducting the weight of the filter, the 
quantity of nitro-cellulose which has remained undissolved 
is found. 

It may here be remarked that perfectly colorless celluloid 
can under no conditions be produced from incompletely- 
dissolved collodion-cotton, though the latter may be used 
for opaque or intensely colored celluloid articles. 

Collodion-cotton to be dissolved must be perfectly free 



CELLULOID. 273 

from water. The wet material is separated as far as pos- 
sible to a flocculent mass resembling wadding and, after 
spreading it out in thin layers upon metal plates, is dried 
with the use of the same precautionary measures as described 
in detail in the manufacture of nitro-cellulose. 

The drying plant need not be of large size, and it should 
be laid down, as a rule, not to dry more collodion-cotton at 
one time than is to be dissolved the same day. By proceeding 
in this manner all danger which may also arise from en- 
tirely dry collodion-cotton is excluded. 

The apparatus in which the solution of the collodion 
cotton and camphor is effected, as well as the preparation 
of the fluid celluloid, consists of an iron cylinder which may 
be constructed of ordinary boiler-plate, but has to be well 
tinned inside. The head of the cylinder is provided with 
an aperture, which can be closed air-tight, for the introduc- 
tion of the solid materials, while on one of the sides the 
<3ylinder is furnished with a pipe for the admission of the 
solvent. Through the centre of the head of the cylinder 
passes the shaft of a stirrer which carries a spiral of tinned 
sheet-iron. The bottom of the cylinder is furnished with a 
discharge pipe for the finished solution, and one side is 
fitted with a small cock for taking samples of the fluid. 

The manner of working with this apparatus is as follows : 
The quantity of camphor intended for the operation is first 
introduced, and then the dry collodion-cotton, when the 
€ylinder is closed and the stirrer slowly set in motion, the 
solvent being at the same time admitted through the side- 
pipe. The stirrer is uninterruptedly kept in slow motion, 
the formation of masses which are simply swollen and im- 
pede solution being thereby prevented. The stirrer is only 
stopped when it is shown by samples taken from time to 
time that solution is complete. 

As regards the solvent to be used there is, in our opinion, 
but one which is actually entirely suitable, namely, pure 
anhydrous ether. Solution of the collodion-cotton may 
18 



274 CELLULOSE, AND CELLULOSE PRODUCTS. 

possibly be hastened by mixtures of ether and alcohol, it 
being asserted by some that such is the case, but they ex- 
ert an injurious influence in working the celluloid masses. 

Pure ether boils at 96.8° F.; absolute alcohol at 172.4° 
F., and the small quantity of water contained in alcohol 
when not absolute, only at 212° F. When the finished 
solution is brought in contact with air, the ether of all the 
fluids present will, of course, evaporate first, so that after a 
certain time the mass contains almost no ether whatever, 
but nearly the entire quantity of alcohol, and most certainly 
all the water. For the evaporation of the alcohol greater 
heat will have to be used and the alcoholic vapors evolved, 
and later on the aqueous vapors also, will form in the mass, 
which has in the meantime become viscous, bubbles which 
cause the celluloid plates to bulge and can only with diffi- 
culty be removed by rolling. Hence to avoid all difficul- 
ties in working, dry collodion-cotton and anhydrous ether 
should only be used. 

The recovery of the ether evaporating from the fluid 
celluloid mass has generally been declared impossible, so 
that it is simply allowed to escape in the form of vapor into 
the air. This procedure, however, has many disadvantages, 
the cost of production being, on the one hand, increased, 
and on the other, it leads to many inconveniences in the 
manufacture itself. By being constantly in an atmosphere 
impregnated with vapors of ether, the health of the work- 
men is likely to be impaired, and in factories working in 
this manner, the workrooms should always be kept thor- 
oughly aired. Another drawback is the great danger from 
fire, as by the mere striking of a match, the mixture of air 
and ether-vapor might be ignited and cause a fearful 
explosion. 

RECOVERY OF THE ETHER. 

By working according to the method described below, 
almost the entire quantity of ether used for the preparation 



CELLULOID. 275 

of the celluloid solution may be recovered, the cost of pro- 
duction thus being considerably reduced. The odor of 
ether can scarcely be noticed in the factory, and there is no 
danger from fire, and injury to the health of the workmen 
is excluded. 

An apparatus of the following construction is used : The 
clear solution of celluloid mass prepared in the manner 
above described, is brought into a sheet-iron cylinder tinned 
inside, and provided on the top with a gutter 4 to 6 inches 
deep, into which fits the rim [of the lid. In the latter is 
fitted a small cock, and above the bottom of the cylinder is 

Fig. 36. 



a pipe with a stop-cock, which serves'^ for the discharge of 
the fluid. The solution to be worked is introduced through 
a pipe furnished with a stop-cock, which enters the cylinder 
at a slight distance below the gutter. The latter is kept 
filled with water, the hydraulic joint thus formed prevent- 
ing the escape of ether-vapor. By this arrangement the 
interior of the cylinder is accessible without difficulty. 
When the cylinder is to be filled with solution, the small 
cock fitted in the lid is opened to allow the escape of air. 

For the purpose of solidifying the solution, a shallow tray 
of the shape shown in Fig. 36 is used. It is constructed of 



276 



CELLULOSE, AND CELLULOSE PRODUCTS. 



tinned sheet-iron and measures 39.37 inches in length and 
width, and 2.36 inches in depth. It is divided into 12 or 
15 compartments by partitions 1.18 inches high, so that 
each compartment is 12.99 inches long, 7.87 (or 9.84) inches 
wide, and 2.36 inches deep. 

Ten such trays W, may be placed one above the other, in 
the ten compartments of a wooden box shown in section in 
Fig. 37. On the right of this box is a small box A, com- 

FiG. 37. 



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municating below with the pipe i2, and connected by means 
of the narrow longitudinal slits o, with the separate com- 
partments in which the trays stand. On the left of the 
box is another small box 5, of the same construction as A^ 
and connected with the pipe R. 

The pipe R^ communicates with the apparatus for con- 
densing the ether-vapors, its arrangement being shown in 
Fig. 38. The pipe R^ terminates in a long, wide tin coil S^ 
lying in a vat kept constantly full of cold water. The 
lower end of the coil passes into the neck of a large flask F^ 
fitted near the bottom with a cock through which the 
condensed ether is drawn off. A narrower pipe S-^ made 



CELLULOID. 



277 



into a coil in a vessel filled with ice and passing out free, 
branches off from the neck of the flask F. 

The operation of preparing solid celluloid with this ap- 
paratus is as follows : One of the trays W, is filled up to a 
mark 1.97 inches above its bottom with solution from the 
cylinder, and placed in the uppermost compartment of the 
box. The other trays having in the same manner been 
filled with solution are then successively placed in the com- 

FiG. 38. 




partments of the box, and the door of the latter is closed 
air-tight. 

By means of a small ventilator, a constant current of 
warm air is slowly conducted through the pipe R, into the 
box. This current of air is produced as follows : In a room 
underneath the workroom, and entirely isolated from it, a 
boiler is bricked in an ordinary fire-place. In this boiler, 
which is filled with water, lies a tin coil open on one end 
and connected on the other, with the ventilator which com- 



278 CELLULOSE, AND CELLULOSE PRODUCTS. 

municates with the pipe R, extending through the floor of 
the workroom. When the water in the boiler has been 
brought to the boiling-point, the air in the coil becomes 
heated, is sucked off by the ventilator, and replaced by 
fresh air flowing in, so that there is constantly a current of 
warm air in the pipe R. The course of the operation is so 
regulated that the current of air moves slowly, and that its 
temperature never exceeds 86° to 89.6° F. Ether boils at 
96.8° F., and should the temperature of the air become that 
high, the mass in the trays might be brought to the boiling 
point and in solidifying be interspersed with bubbles. The 
current of warm air enters through the narrow slits o, by 
means of which the box A is connected with the compart- 
ments in which the trays stand, and in passing to and fro 
over the surface of the fluid, becomes impregnated with the 
vapors of the ether. It then enters the box B, and passes 
through the pipe R^ into the coil S^ which is surrounded by 
cold water. The greater portion of the ether contained in 
the air condenses to fluid and collects in the flask F, from 
which it is from time to time drawn off". The air escaping 
from F, can only pass out through the coil Sj^ which ter- 
minates outside the workroom. The coil S^ lying in the 
vessel filled with ice, the last traces of ether are condensed 
and run back into the flask F. 

With the use of these contrivances, the evaporation of 
the ether in the celluloid solution is very rapidly effected, 
and the contents of the trays are gradually converted into 
a mass somewhat resembling congealing glue. The depth 
of the layer of fluid in the tray, which was originally 1.97 
inches, having been constantly reduced by the evaporation 
of ether, and the height of the partitions being but 1.18 
inches, each compartment, when evaporation has progressed 
to a certain degree, will contain a body representing, when 
the mass has become perfect!}^ dry, a prism 12.99 inches 
long, 7.87 inches wide, and about 0.98 inch thick. When 
drying is finished, each of these prisms ma}^ be obtained by 



. , - CELLULOID. - 279 

itself by turning the tray upside down, and the dimensions 
of these prisms are just right to allow of their being con- 
veniently worked with suitable rolls. Drying of the cellu- 
loid mass may be considered complete, when a sample 
prism taken from one of the trays can be cut like quite 
solid cheese. 

THE DRYING CHAMBER. 

The prisms taken from the trays are placed in a drying 
chamber heated by warm air and provided with a pipe ter- 
minating either in the open air or in a chimney. The 
temperature of the chamber may be 104° to 113° F., the 
last traces of ether still adhering to the mass being thereby 
evaporated. The drying chamber is furnished with frames 
covered with nets of stout twine upon which the prisms are 
placed so that they rest upon one of their narrow longi- 
tudinal sides. They remain in the drying chamber till 
they form a hard, horn-like mass, and the fracture of a 
broken piece presents a perfectly uniform appearance, a 
lardaceous appearance of the fracture being indicative of 
insufficient drying. 

If the crude celluloid is to be rolled, it has to be heated 
to acquire sufficient plasticity, and the drying chamber may 
also be used for this purpose. When drying is finished a 
current of air having a temperature of 140° to 158° F. is 
conducted into the chamber, this temperature sufficing to 
give to the celluloid the required softness. One plate after 
the other may then be taken from the chamber and passed 
through the rolls. 

The preparation of celluloid with the assistance of the 
contrivances described above, presents many material ad- 
vantages, it being possible to prepare in a short time in a 
small room larger quantities of celluloid, and recover almost 
the entire quantity of ether required for making the solu- 
tion. The workmen are not exposed to the vapors of ether, 
and there is no danger from fire during the entire operation. 



280 CELLULOSE, AND CELLULOSE PRODUCTS. 

The plates of crude celluloid obtained by the above- 
described method are either entirely colorless or of a slightly 
yellowish color. However, even if they show the latter 
color, they should be perfectly uniform throughout their 
entire bulk, dull and cloudy spots imbedded in the trans- 
parent mass being indicative of the solution used having 
contained particles of nitro-cellulose only swollen but not 
dissolved. As previously mentioned, such defective cellu- 
loid may be used for the preparation of masses which are to 
be colored, or filled. Dull spots may sometimes disappear 
by long-continued rolling. 

The dried material does not yet possess the great hard- 
ness and elasticity characteristic of celluloid, it acquiring 
these properties only by mechanical manipulation, the first 
step being rolling, and the more frequently this operation 
is repeated and the greater the pressure applied, the better 
the quality of the product will be. It would therefore seem 
that by this purely mechanical process, a change in the 
position of the finest particles of the celluloid is effected. 

PROPERTIES OF CELLULOID. 

Celluloid prepared in a proper manner forms, as pre- 
viously mentioned, a colorless or very slightly yellow mass 
closely resembling horn, or still more so, tortoise shell. It 
represents a mass with a slight odor of camphor, becoming, 
however, in the course of time entirely odorless by reason 
of the evaporation of the particles of camphor lying near 
its surface. By vigorously rubbing or heating an article of 
celluloid, the odor of camphor becomes more pronounced. 

At the ordinary temperature, rolled celluloid is very hard 
and extraordinarily elastic, and thicker pieces of it can 
scarcely be broken. It may be sawed, planed and turned 
in the lathe like fine-grained wood. A thin plate of it may 
be cut with the scissors, it behaving in this respect, some- 
what like very solid cardboard. 

Celluloid, firm and brittle as it is at the ordinary tem- 



CELLULOID. 281 

perature, may b}^ suitable heating be changed into a very 
plastic mass which can be moulded into any desired shape. 

Celluloid being a bad conductor of heat, larger pieces of 
it to be rendered plastic have to be for a longer time ex- 
posed to an adequate heat, otherwise they would offer too 
much resistance in rolling or pressing. Celluloid becoming 
quite plastic at a temperature of 158° F., pieces of it are 
most conveniently worked by throwing them in a vessel 
full of boiling water, covering the vessel, and allowing the 
whole to stand quietly for some time, when by samples 
taken from the vessel it is ascertained whether the pieces 
are sufficiently plastic. 

The plasticity of celluloid increases considerably at a 
higher temperature. When heated to between 248° and 
302° F., it is as plastic as wax, and like it, can be given 
any shape desired by pressing it in a mould, or two pieces 
of the hot mass may be made into one by pressure. 

If heating the cellulose be effected so that the rise in the 
temperature can be accurateh'' determined, it will be noticed 
that up to nearly 284° F. no other change takes place 
besides greater softness and plasticity. If, however, the 
temperature be increased to 284° F., a molecular change 
takes place ; the mass suddenly becomes opaque, and by 
slightly raising the temperature, at the utmost to 293° F., 
spontaneous decomposition sets in. The mass puffs up very 
much and decomposes, a heavy smoke being evolved. 
However, there is no explosion, this being a proof that the 
celluloid no longer contains nitro-cellulose. 

On coming in contact with a burning body, celluloid 
ignites very readily, and burns with a yellow, luminous, 
sooty flame, the odor of camphor, caused by the evaporation 
of this substance being very pronounced. When the flame 
of the burning celluloid is blown out, combustion continues 
very rapidly without flame, vapors of camphor ascending 
constantly from the glowing mass. The process which 
thereb}'^ takes place consists in that the nitro-cellulose, by 



282 CELLULOSE, AND CELLULOSE PRODUCTS. 

reason of its liigh content of oxygen, continues to burn, and 
the camphor evaporates in consequence of the heat devel- 
oped, the temperature being, however, not sufficiently high 
for the ignition of the camphor vapors. 

Towards solvents, celluloid behaves quite indifferently. 
In water it remains entirely unchanged and, by reason of 
this property, it is used for making syringes, basins, etc., 
for surgical purposes. When placed for some time in strong 
alcohol, it swells up very much, but does not dissolve, solu- 
tion being gradually effected only by the addition of ether. 
B}'^ being allowed to stand in the air, the solution yields 
celluloid with its original properties. When left for a 
longer time in contact with sulphuric acid, it is completely 
dissolved, and concentrated nitric acid dissolves it without 
residue. By ^concentrated soda lye it is only dissolved when 
remaining for a longer time in contact with it. 

The physical properties of celluloid are the same as those 
of horn, wood and wax. In mechanical manipulations 
such as cutting, sawing, planing, turning, it can be treated 
just like horn or wood, and in fact behaves to better ad- 
vantage for the operator as, being a structureless substance, 
it can in the same manner be worked in every direction. 
Like wax, it possesses the property of being by heat con- 
verted into a very plastic substance which can readily be 
brought into any desired form. It commences to become 
plastic at about 122° F., and plates of it heated to this tem- 
perature may be rolled under strong pressure. At a higher 
temperature its plasticity increases considerably and, as a 
rule, one of 212° F. suffices for all kinds of operations by 
rolling or pressing. At 248° F. it becomes soft enough to 
allow of two pieces being made into one by kneading. 

One of the most prominent properties of celluloid is its 
great tenacity combined with uncommonly great elasticity. 
A stick of it as thick as a finger can at the ordinary tem- 
perature be bent to and fro, regaining its original form 
when the tension ceases : no flaws or cracks are formed 



CELLULOID. 283 

even by frequently repeated bending, and such a stick can 
scarcely be broken. However, when exposed to a very low 
temperature celluloid has a tendency to become brittle. 

WORKING CELLULOID. 

The masses obtained by completely drying the pieces and 
by evaporating celluloid solutions, do not show the great 
hardness, elasticity and high lustre possessed by articles pre- 
pared from them, but are of a more or less soft nature, hav- 
ing in this respect a certain resemblance to not entirely 
dried gelatine. These properties appear only by vigorous 
mechanical manipulation, a change in the position of the 
smallest particles of the mass being probably effected, or 
they are more closely drawn together than is the case in 
the mass when simply dried. 

The mechanical manipulation of celluloid should always 
commence with rolling the plates. For this purpose, the 
sufficiently dried plates are heated in the drying chamber 
to between 140° and 158° F., and thrown into hot water 
where they are allowed to remain till heated throughout. 
It is of great importance that the plates should be heated 
throughout their entire thickness, as otherwise they would 
tear laterally under the rolls. 

For the purpose of rolling, smooth steel rolls, so arranged 
that the distance between them can be regulated at will, 
are used. In order to be able to carry on the work rapidly, 
it is advisable to place several such pairs of rolls one behind 
the other, the rolls of each succeeding pair being more 
closely set than those of the preceding one, so that the plate 
which has been drawn out in the first pair of rolls is rapidly 
converted into a very thin plate. By working in this man- 
ner, the plate need only to be heated once, enough heat to 
keep it sufficiently soft being developed by the pressure. 

The thin plates thus obtained are placed together and 
are sufficiently heated to allow of their being welded to- 
gether when rolling is repeated. The more frequently roll- 



284 CELLULOSE, AND CELLULOSE PRODUCTS. 

iiig is repeated and the greater the pressure, the more 
tenacious, elastic and lustrous the celluloid will be. Ac- 
cording to the purpose to which the celluloid is to be 
applied, thinner or thicker plates of it are prepared by 
rolling. For further working these plates are sufficiently 
heated, and articles prepared from them, as a rule, bj'' 
stamping or pressing in warmed hollow moulds. 

COLORING CELLULOID, 

Like artificial silk, celluloid possesses the property of 
being readilj^ colored, it taking up with special facility the 
soluble tar colors. If an article of colorless celluloid be 
only for a short time placed in the solution of a dye- 
stuff, the surface only will be colored, the interior remain- 
ing colorless, but if left in it for a sufficiently long time, it 
will be colored throughout its entire mass. Even compara- 
tively thick articles appear uniformly colored upon their 
cross sections if left long enough in the solution. It may, 
therefore, be supposed that solutions of dye-stuff penetrate 
the celluloid mass like a sponge, and that the separate 
particles of the coloring matter are held by the smallest 
particles of the celluloid mass. 

As there are soluble tar-colors of all shades, any desired 
color may be given to celluloid, and the resulting product 
is distinguished by being perfectly transparent, very lustrous 
and smooth, surpassing in this respect the finest quality of 
colored gelatine. 

Transparent celluloid articles are, as a rule, colored a 
beautiful golden yellow, which is readily produced b}'^ plac- 
ing them in picric acid solution. 

Celluloid of any desired color may be readily obtained, 
and there are several ways of producing articles from the 
colored material. The' most simple way is to color the 
celluloid while it is being prepared. This is effected by 
mixing with the celluloid solution when finished, coloring 
matter soluble in alcohol, the solution being by vigorous 



CELLULOID. 285 

stirring distributed throughout the fluid in order to obtain 
a uniformly colored product. A certain quantity of cellu- 
loid of the same uniform color is thus obtained. However, 
as celluloid of different colors has to be used for various 
purposes, this method of direct coloring while preparing 
the mass, notwithstanding its convenience, is only em- 
ployed in exceptional cases, it being preferred to color the 
finished articles. 

The simplest plan, as previously mentioned, is to use 
tar-colors soluble in alcohol, they being readily taken up 
by the celluloid, and it is only necessary to allow the 
articles to remain in the solution till they are sufficiently 
colored. They are then taken out, rinsed in water, and 
made lustrous by vigorous rubbing with a soft cloth. 

However, there is a way of producing certain color effects 
more beautiful than can be done with tar colors, and below 
a few hints regarding this manner of coloring are given. In 
this operation it has to be borne in mind that the coloration 
depends on the concentration of the solutions used ; the 
more saturated they are, the deeper the coloration will be. 
It is advisable to learn by a few small experiments the re- 
quired concentration of the solutions to be used. A beauti- 
ful yellow may be produced by placing the article first in 
solution of acetate of lead in water, then slightly rinsing it 
in clean water, and finally bringing it into a solution of 
potassium dichromate to which sufficient soda has been 
added to color it yellow. By this means the beautiful 
yellow combination known as chrome yellow is formed in 
the pores of the celluloid. 

Red may be produced in various ways. A very beautiful 
scarlet is obtained by placing the articles for a short time 
in water which has been compounded with a small quan- 
tity of nitric acid, and then bringing them into a fluid ob- 
tained by treating finely-powdered cochineal with ammonia. 
When the desired shade of color has been attained, the 
articles are taken from the solution, and thoroughly rinsed 



286 tl'ELLULOSE, AND CELLULOSE PRODUCTS. 

in water. A dark, peculiar red is obtained by treating the 
articles first with a solution of potassium chromate, and then 
with a solution of nitrate of silver, the beautiful red silver 
chromate being thereby formed. A magnificent purple-red 
is obtained by placing the articles in a highly dilute solu- 
tion of trichloride of gold, and then exposing them to the 
direct sun light. By the action of the latter the chloride of 
gold is decomposed and the celluloid colored. 

Blue may also be obtained by various means. Indigo- 
blue is produced by simply placing the celluloid in dilute 
solution of indigo-carmine in water. Another very beauti- 
ful blue, the so-called Berlin-blue, is obtained hy placing the 
articles in a solution of ferric chloride in water, rinsing, and 
bringing them into a solution of yellow prussiate of potash. 

Green is obtained by placing the celluloid in a solution 
prepared from 2 parts of verdigris and 1 part of ammonium 
chloride. 

Violet may be produced by first dyeing the articles 
slightly blue with indigo, and then treating them with 
cochineal solution till the desired shade of violet appears. 

Brown. Prepare a solution of permanganate of potash in 
water, add to it soda solution so that no precipitate is 
formed, and place the articles in the fluid. 

Gray. Silver-gray is obtained by placing the articles in 
a very dilute solution of acetate of lead, and then bringing 
them into an atmosphere of sulphuretted hydrogen. The 
lead sulphide formed shows a peculiar, metallic, lustrous, 
gray color. It is, however, absolutely necessary to use, as 
above mentioned, a very dilute solution of acetate of lead, 
otherwise the color will be black instead of gray. 

Black. Mix solution of logwood extract with solution of 
tannin in water and allow the articles to remain fn the 
mixture for a few hours. They are then rinsed in water and 
placed in ferrous sulphate (green vitriol) solution whereby 
they acquire a deep black color. Another metallic, lustrous 
black is obtained by placing the articles in nitrate of silver 



CELLULOID. 287 

solution ; according to the concentration of the solution the 
color will be gray to deep black. 

PRINTING ON CELLULOID. 

By reason of its smooth, surface, ordinary printing inks 
do not adhere well to celluloid and, without special treat- 
ment, it would be impossible to print on it in colors. 

To make a celluloid plate suitable for being printed on, 
its surface has to be provided with a fine graining in a 
manner similar to that in which a lithographic stone is 
prepared. Celluloid possessing, however, a comparatively 
slight degree of hardness, graining is effected by means of 
a small sand blast, the originally lustrous plate becom- 
ing thereby matt. The plate is then well washed with 
water to remove all the celluloid dust, and is then thor- 
oughly dried. It is next coated with a varnish consisting 
of equal parts of a fine quality of pale linseed-oil varnish 
and colorless copal varnish diluted with enough oil of tur- 
pentine so that the varnish can spread, like collodion, over 
the plate. The plate is coated with this varnish in exactly 
the same manner as a glass plate with collodion for photo- 
graphic purposes. The excess of varnish is allowed to run 
back into the flask, and the plate is set on edge to dry. 

A plate thus prepared can be printed on in the press in 
various colors, the latter adhering as well as on paper. If, 
after the colors are dry, the plate is coated with a thick cel- 
luloid solution and the latter, when congealed, is polished 
with a soft, woolen stuff, the printing ink lies under a layer 
of celluloid, and the plate may be cleansed without fear of 
effacing the printing. 

Celluloid articles may also be provided with pictures of 
various colors by means of a process closely resembling that 
employed for the production of the so-called transfer pictures 
or metachromatypes. According to this process the pictures 
are in inverted succession printed in colors on thin paper, 
and the finished impression is finally coated with a mass 



288 CELLULOSE, AND CELLULOSE PRODUCTS. 

which by moistening becomes very sticky. In transferring 
the pictures to glass, wood, porcelain, etc., this coating is 
moistened, and the paper, coated side down, is laid upon the 
article to which it is to be transferred, and firmly pressed 
against it. After a short time the paper is softened by 
moistening the back, and is then carefully drawn off, start- 
ing from one point. The paper peels off smoothly from the 
picture, the latter remaining attached to the basis. 

If this process is to be applied to the ornamentation of 
celluloid articles, the colors used for the production of the 
picture have to be mixed with a body readily soluble in 
strong alcohol, soft copal finely pulverized being a suitable 
material for this purpose. When all the colors have been 
printed, the printed portions of the paper receive an addi- 
tional impression made with spirit copal varnish, the rest 
of the paper remaining free. 

, For the purpose of transferring such a transfer picture to 
celluloid, the surface of the latter is moistened with strong 
alcohol, which causes the uppermost layers of the celluloid 
to swell up, and the paper, picture side down, is laid upon 
the plate thus prepared. The latter is then covered with a 
glass plate and the whole placed in a press where it remains 
for a few hours under slight pressure. When there can be 
no doubt of the transferred picture adhering firmly and 
having become dry by the evaporation of the alcohol, the 
plate may be laid in water, and the paper, when sufficiently 
softened, carefully drawn off from the picture. 

For the protection of the picture and to make it at the 
same time durable, it may be coated with a layer of cellu- 
loid by pouring celluloid solution over it. If imitation 
gold or silver has been used in printing the pictures, this 
coating with celluloid is of special importance, because 
these materials, when exposed to the air soon loose their 
metallic lustre, and the pictures become unsightly. If, 
however, the pictures when just finished are provided with 
•a layer of celluloid, no matter how thin, the colors are en- 



CELLULOID. 289 

tirely excluded from the action of the air and retain their 
metallic lustre. 

Printing on celluloid in the same manner as pictures in 
many colors are produced on paper, has also been recently 
successfully accomplished by the use of tar colors soluble in 
concentrated acetic acid, the colors adhering firmly and 
retaining their sharp outlines without running into each 
other. These colors, as shown by microscopical examina- 
tion, strongly attack the celluloid, penetrating to a great 
depth, in consequence of which they adhere firmly. How- 
ever, as metals are also attacked with great energy by 
acetic acid, metallic printing blocks cannot be used in this 
case, and blocks of a material entirely indifferent towards 
acetic acid have to be substituted for them, gutta-percha 
being especially suitable for this purpose. Such printing 
blocks can be readily made by taking *a' plaster of Paris 
cast from the original — an engraved metal plate, or a wood- 
cut — laying upon it, a gutta-percha plate previously softened 
in hot water, and subjecting the mould together with the 
gutta-percha plate to pressure in a press till the gutta-percha 
has again become hard. The plate then shows all the de- 
pressions and elevations of the original plate, and may at 
once be used for printing. 

CELLULOID WITH FILLING MATERIALS. 

Celluloid can without difficulty be worked with indifi^er- 
ent bodies into uniform masses, the substances thus ob- 
tained possessing, in addition to the hardness and elasticity 
of celluloid, other properties which make them suitable for 
the preparation of various specialties. 

Although all kinds of perfectly dry substances in a pul- 
verulent form may be used as filling material, white pul- 
verulent bodies are, as a rule employed, the resulting masses 
being of course opaque. 

However, since so-called white bodies are colorless and 
the effect appearing as white to the eye is simply due to the 
19 



290 CELLULOSE, AND CELLULOSE PRODUCTS. 

peculiar reflection of the light, masses presenting a very 
characteristic appearance may be prepared from these bodies 
and from celluloid. 

By mixing with the colorless celluloid only a small quan- 
tity of the powder of a white body, masses are obtained 
which, though appearing white, are to a certain degree 
transparent. Milk poor in fat presenting the same appear- 
ance. Masses of this kind are called milk-white, and articles 
of a beautiful milk-white color maj'' be made from celluloid. 
Ivory also appears translucent, but its color is not pure 
white, it always showing a yellowish tinge. Now, there is 
no difficulty whatever in mixing a white pulverulent body 
in suitable quantity with a yellow one, and by combining 
this mixture with celluloid, masses are obtained which, as 
regards color, bear a close resemblance to ivory. 

If colorless cellliloid be mixed with a suitable quantity of 
a pure white body, masses resembling in appearance polished 
white marble are obtained. By the addition of powders of 
a different shade, the color of such masses may be toned 
down as much as desired. 

The following materials may be used: Magnesia, chalk, 
talcum or starch. For certain masses which are to be very 
heavy, artificially prepared barium sulphate (permanent 
white), or zinc white may be employed. 

Celluloid masses of light weight being especially desirable 
for the manufacture of cane heads, etc., a white powder of 
slight specific gravity is, as a rule, used as filling material, 
magnesium powder deserving, in this respect, preference 
above all others. 

The filling material may be combined with the celluloid 
either in the preparation of the latter itself, or by working 
it into the finished product. 

In working according to the first method, the mixture of 
the viscous celluloid solution with the powder is best effected 
in a contrivance resembling in its construction a revolving 
barrel, it consisting of a tinned sheet-iron cylinder revolv- 



CELLULOID. 291 

ing around its axis. The quantity of the solid body to be 
used having been introduced, the celluloid solution is al- 
lowed to run in, and the cylinder closed air-tight. The 
cylinder should at the utmost be filled three-quarters full. 
It is then slowly revolved by means of a mechanical con- 
trivance, the operation being continued till the fluid has 
combined with the powder to a viscous mass of the appear- 
ance of cream. 

This fluid is discharged into the vessels in which it is to 
coagulate and the mass, when solidified, is thoroughly dried, 
the product obtained being white celluloid plates. In cut- 
ting such a plate in two, it will frequently be observed that 
the portion of it which had been in contact with the bottom 
of the coagulating vessel is pure white, while the opposite 
portion is milk-white, this being readily explained by a 
portion of the powder having subsided in the fluid while at 
rest. This is, however, of no consequence, the coloration 
becoming uniform by itself, if in the subsequent rolling of 
the mass the thin plates are put together, and again rolled. 

The other method for combining the pulverulent filling 
substance with the celluloid, consists in uniformly scattering 
the powder upon the celluloid plates previously softened, 
and rolling them repeatedly till the color is uniform 
throughout. 

Celluloid masses combined with a filling substance may 
also be colored, and articles of very handsome appearance 
made from them. Special mention may here be made of 
imitations of genuine coral which, from the most delicate 
milk-white, or only slightly rose-tinged, kinds up to the 
deep cinnabar-red varieties, can be produced of such beauty 
as to be distinguished from the genuine article perhaps 
only by their higher lustre. 

Although filled celluloid masses colored yellowish in a 
suitable manner closely resemble ivory in appearance, they 
can at once be distinguished from ivory by the absence of 
the peculiar texture characteristic of the latter. However, 



292 CELLULOSE, AND CELLULOSE PRODUCTS. 

this texture is also successfully imitated, the resemblance 
between celluloid imitations and genuine ivory becoming 
thereby still greater. 

For this purpose plates of filled celluloid mass, some of 
them pure milk-white and others of a color inclined to 
yellow, are used. These plates are alternately laid one 
upon the other, heated, and then rolled. By the pressure of 
the rolls the separate plates are welded together, and by 
being stretched under the rolls, of course, become con- 
stantly thinner, so that the layers of a darker and lighter 
color are only visible upon the cross-section in the form of 
fine lines running into each other. If a plate thus rolled, 
previous to being made into a cane head, button, etc., is 
bent to and fro, the fine lines are also bent, and such an 
article has to be very closely examined in order to find out 
that it is only an excellent imitation of, instead of genuine, 
ivory. 

Tortoise shell can be so closely imitated with celluloid 
that it can only with certainty be determined by a chemi- 
cal examination, whether the article in question is made of 
genuine tortoise shell or is an imitation of it. For the pur- 
pose of imitating tortoise shell, a celluloid plate is first col- 
ored exactly the ground color of genuine tortoise shell, 
solution of picric acid to which a suitable quantity of ani- 
line brown has been added being used for the purpose. 
The peculiar red-brown markings characteristic of tortoise 
shell are applied by means of a paint-brush with aniline- 
brown solution to which a small quantity of fuchsin has 
been added. Such solutions when prepared with very 
strong alcohol, penetrate deeply into the celluloid mass. 

The celluloid plates used for imitations of tortoise shell 
are highly polished previous to being colored and painted, 
this being best effected by pressing them against a rapidly 
revolving cylinder covered with a soft woolen stuff. Since 
the painted places lose somewhat in lustre, the plates when 
finished must again be carefully polished. 



CELLULOID. 



293 



MOULDING CELLULOID ARTICLES, 

Pure celluloid, as well as that mixed with filling sub- 
stances, can in a simple manner be brought into any desired 
form, it becoming, as previously mentioned, so plastic at 
212° F., as to equal, in this respect at least, warmed wax. 

When celluloid is to be converted by rolling into plates 
of any thickness, the simplest plan is to place the thicker 
plates in hot water until sufficiently softened, and then roll 
them out as thin as desired. 

In case celluloid masses of greater thickness are to be 

Fig. 39. 




shaped by stamping or pressing, it is advisable to use a spe- 
cial heating apparatus capable of holding a larger quantity 
of celluloid, so that without interruption in the work, heated 
pieces may be constantly taken out, and replaced by pieces 
to be heated. An apparatus very suitable for this purpose 
is shown in Fig. 39. J. is a cubical box of stout sheet-iron. 
It is surrounded by another sheet-iron box B, the distance 
between the walls of the two boxes being 2 to 2|- inches. 
The outside of the box B, with the exception of the bottom, 
is covered with thick felt and the latter with wood. The 
outside of the thick wooden door of the box A is also cov- 
ered with felt and wood. From the top of the box B as- 
cends a pipe B, 0.79 to 1.18 inch in diameter. This pipe 



294 CELLULOSE, AND CELLULOSE PRODUCTS. 

terminates in a spiral, open on top, in a cooling vessel 
filled with cold water. The space between the boxes A and 
B is filled with water, and the bottom of B is heated by 
means of a small stove upon which the apparatus stands, 
or, if the latter is small, by a gas flame. The celluloid 
masses are placed upon zinc plates fixed one above the 
other in the box A. When the water between the two 
boxes has been brought to the boiling point, the temper- 
ature in the box A will in a short time rise to 212° F., and 
the celluloid masses will, according to their thickness, be 
in a shorter or longer time heated to the same temper- 
ature. The box A is only opened for taking out heated cel- 
luloid, or for placing pieces to be heated in it. 

Since the water by boiling evaporates, it would be nec- 
essary from time to time to replenish it. This is, however, 
rendered superfluous by the cooling arrangement, by means 
of which the steam rising through the pipe R into the spiral 
portion of the latter in the cooling vessel is condensed, and 
the hot water falls back into the space between the two 
boxes. When work for the day is finished and the fire 
under the apparatus extinguished, the water, by reason of 
the insulation of the outer box by felt and wood, remains 
quite hot till the next morning, and but little time is re- 
quired to bring it to the boiling point. 

Celluloid tubes are made as follows : A plate of celluloid 
is cut rectangularly in such a way that it accurately fits 
around a cylinder corresponding to the inside diameter of 
the tube to be made. The cylinder being heated, the 
softened celluloid plate is laid around it, and a round piece 
of sheet metal is pushed over the plate so as to hold it in 
position without entirely covering it. Fluid celluloid is 
applied to the joint of the plate, and the whole is then left 
untouched till the celluloid is cold. The finished tube is 
then drawn from the cylinder. 

It may here be mentioned that for the purpose of joining 
two pieces of celluloid, it has been recommended to soften 



CELLULOID. 295 J 

them by the application of strong alcohol, and then press 
them together. Celluloid solution obtained by dissolving 
nitro-cellulose and camphor in ether is, however, more 
suitable for the purpose, it solidifying in a very short time, 
and the two pieces are then joined together by the same 
mass of which they themselves consist. 

If celluloid is to be shaped by pressing, it is advisable, 
especially when making a large quantity of articles of the 
same form, to put the lower portion of the mould in the 
press in such a way that it can constantly be kept, b}'^ means 
of a gas flame, at a temperature which need not be above 
158° F. In preparing articles from heated celluloid in a 
press thus arranged, tearing of the mass on the edges need 
not be feared, and, with some dexterit}'^, the pressed article 
can, while still soft and without losing shape, be lifted 
from the mould, the latter being thus left available for the 
next operation. 

Imitations of corals may be made in various ways, accord- 
ing to the form the separate pieces are to have. Corals of 
cylindrical shape are cut with a circular saw from sticks 
made by pressing. Rounded-off (barrel-shaped) corals are 
stamped from the above-mentioned cylindrical sticks, and 
pierced in the lathe. The final finish is given to the corals 
by brightening them by means of rapidly revolving bobs 
covered with soft cloth. 

The use of celluloid masses for the manufacture of all 
kinds of combs is of great importance. They are made by 
first rolling a celluloid plate in such a way that one of its 
narrow sides, which is to form the back of the comb, is 
thicker than the other. The comb is then stamped from 
the softened plate. The teeth are cut with a rapidly re- 
volving circular saw kept cool by water dripping upon it, 
and the finished comb is finally polished. 

CLICHES FROM CELLULOID. 

A very important application of celluloid for the repro- 



296 CELLULOSE, AND CELLULOSE PRODUCTS. 

duction of printed matter consists in its use for cliches 
which, independent of being non-breakable, are very dur- 
able so that thousands of impressions may be made, with- 
out their sharpness being in an}^ way diminished. The 
production of such cliches, either from a form of type or a 
wood-cut, is a very simple operation, and is effected as 
follows : A plaster of Paris cast is first made of the form or 
wood-cut, the best quality of plaster of Paris such as is used 
for art castings being employed for the purpose. To make 
the cast harder, saturated solution of alum in water is used, 
in place of ordinary water, for mixing the plaster of Paris. 
Such cast requires a longer time for hardening than one 
prepared in the usual way, but it possesses much greater 
hardness. When thoroughly dry the cast is saturated with 
solution of shellac in strong alcohol ; with casts from wood- 
cuts this saturation is effected by applying the shellac solu- 
tion with a soft brush. 

The plaster of Paris mould is then placed in a press and 
covered with a heated celluloid plate of suitable thickness. 
The press is then slowly and very uniformly tightened to 
give the softened celluloid time to penetrate into ail the de- 
pressions of the mould. The press is finally tightened, and 
left untouched till the celluloid is cooled to the ordinary 
temperature. The celluloid plate is then detached from 
the mould by carefully knocking the latter against a solid 
support, and the mould, which is not in the least damaged, 
may be used for making another cliche. 

When a celluloid cliche properly made is examined with 
a magnifying glass, it will be seen that the smallest details 
have been reproduced, and it need only to be blocked to be 
ready for printing. 

Stamps, the text of which is composed of types may in a 
similar manner be made from celluloid, such stamps hav- 
ing the advantage over rubber stamps of being more easily 
made and being more durable. 



CELLULOID. 297 

COLLARS AND CUFFS FROM CELLULOID. 

Masses of celluloid and a white filling-substance are well 
adapted for the manufacture of collars and cuffs which, as 
regards appearance, can scarcely be distinguished from 
such articles made of the finest quality of linen, and they 
have the advantage of greater durability and being more 
easily cleansed, though the latter can only be done when 
properly treated. 

The white masses for this purpose are prepared from 
celluloid and zinc-white, or magnesia, or chalk, and rolled 
out to plates. Pieces of the shape of the collar or cuff are 
then stamped from these plates. 

For the purpose of giving these pieces the appearance of 
a fine quality of linen, a mould is made as follows : A col- 
lar of fine linen is used as a model, and a plaster of Paris 
cast made of it. From this plaster of -Paris cast hollow 
moulds of type metal are made. The stamped celluloid 
plates being heated are laid in the moulds, and subjected to 
pressure by means of a press. The fine threads constituting 
the tissue of the collar used as a model will be found re- 
produced true to nature upon the celluloid so that, in 
appearance, it cannot be distinguished from the linen collar. 

Celluloid collars and cuffs, like the genuine linen articles, 
become dirty by use, and it is claimed they can be cleansed, 
•so as to appear like new, by simply brushing them with 
soap and water, and rinsing in water. This, however, is 
not in accordance with the facts, it being impossible in this 
manner to remove the dirt, and, notwithstanding a vigorous 
use of the brush, the article does not become perfectly clean. 
The reason for this is that celluloid mixed with a large 
quantity (up to 50 per cent.) of filling-substance is by no 
means an impervious material like pure celluloid ; on the 
contrary, it is quite a porous mass in which the particles of 
dust settle so firmly that they cannot be removed by brush- 
ing with soap and water. The impossibility of thoroughly 



298 CELLULOSE, AND CELLULOSE PRODUCTS. 

cleaning celluloid cuffs and collars may probably be the 
reason why they have not been more generally introduced. 
For the production of celluloid collars and cuffs which 
can actually be readily cleansed, it would seem necessary to 
provide the finished article with an impervious coating, 
pure colorless celluloid being used for this purpose. This 
coating is prepared by adding, for the purpose of dilution, 
a certain quantity of absolute alcohol to fluid celluloid — 
i. e., solution of nitro-cellulose and camphor in ether. The 
finished articles are for one moment dipped in the solution, 
whirled around to remove every drop of solution, and hung 
up free in the air. When the solvent is evaporated, which 
will be the case in a very short time, the articles will look 
as having been starched with gloss-starch, their beautiful 
appearance being due to the thin layer of colorless celluloid 
with which they have been provided. Such, so to say, 
lacquered celluloid collars and cuffs may be cleansed in a 
very simple way by spreading them out smoothly and 
rubbing with a sponge dipped in lather, drying, and vigor- 
ously rubbing with a soft cloth. A brush should not be 
used, as by rubbing with it the thin layer of celluloid would 
soon lose its beautiful gloss. By this simple treatment 
lacquered collars and cuflfs can be actually cleansed, and 
besides are more durable than linen articles which after 
having been several times washed, are frequently so much 
the worse for wear as to be useless. 

CELLULOID FOR DENTISTS' USE. 

In modern times celluloid is more and more employed 
by dentists, it having gradually supplanted hard rubber, 
which was formerly in general use for the manufacture of 
sets of artificial teeth. 

The celluloid to be used for this purpose must be of ex- 
actly the same color as the gums, and the only dye-stuff 
suitable for coloring it is cinnabar, on account of its indif- 
ference towards the action of the saliva and food. For the 



CELLULOID. 299 

purpose of preparing an intimate mixture of celluloid and 
cinnabar, the latter has to be reduced to an impalpable 
powder by levigation. It is best to commence the operation 
by covering a thin, softened plate of celluloid with cinnabar 
powder, placing another also very thin celluloid plate upon 
it, and joining the two plates by rolling, the cinnabar be- 
coming thereby fixed. The plate thus obtained is folded 
together, heated and again rolled, this operation being re- 
peated till the celluloid is uniformly colored throughout. 
The work of preparing in this manner a uniform mass 
being quite troublesome, it would seem advisable to prepare 
at one operation a larger quantity of such celluloid, and 
make it finally into plates of the thickness suitable for the 
use of dentists. 

An exact impression of the gums and jaw as required for 
making a set of artificial teeth is made, as is well known, 
with plaster of Paris, and the negative thus obtained is 
made use of for preparing the plates. In making these 
plates from rubber, an impression in soft rubber is made 
from the plaster of Paris negative, and heated in the vulcan- 
izing apparatus till it is converted into hard rubber. In 
working with celluloid, the preparatory operations are the 
same as with rubber. The celluloid which is to be used for 
the plates is heated till it is very plastic, and then firmly 
pressed upon the plaster of Paris cast, remaining thus under 
pressure till the whole is cooled down to the ordinary tem- 
perature. 

The temperature to which the celluloid, to be used for 
plates, has to be heated, is given by dentists as 282° F. 
However, this is probably too high, celluloid at this degree 
of heat approaching the point at which it is decomposed. In 
our opinion, a temperature of 266° to 275° F. is amply suf- 
ficient to make the celluloid so plastic as not to require even 
especially high pressure to force it into the finest depres- 
sions of the mould. Care must, however, be taken to heat 
the celluloid throughout to the above-mentioned degree 
before pressing is commenced. 



300 CELLULOSE, AND CELLULOSE PRODUCTS. 
OBJECTS OF ART FROM CELLULOID. 

By reason of its great plasticity, when heated, celluloid 
may to advantage be used for the manufacture of all kinds 
of inlaid work, and with it as a basis-material, beautiful 
mosaics can be produced, as well as fancy articles inlaid 
with metal, the latter being generally made of celluloid 
masses representing an imitation of ivory or tortoise shell. 

The metals used for these incrustations are gold and silver 
for valuable articles, and bronze, copper, and aluminium 
for cheaper goods. The metals are used in the form of very 
thin sheets, from which are cut by means of suitable dies, 
stars, bands, leaves, ornaments, monograms, etc. 

These small particles of metal are attached to the cellu- 
loid by moistening them with strong alcohol, or still better 
with fluid celluloid, and placing them in their proper posi- 
tions for the execution of a fixed design. 

When the entire design has thus been produced, the 
celluloid plate is placed upon a firm, level support, for in- 
stance a piece of thick zinc-sheet, and uniformly heated to- 
gether with the latter to 257° F. The plate together with 
the support is then drawn through rolls, a very slight pres- 
sure being first given for the purpose of pressing the parti- 
cles of metal into the soft celluloid mass. In passing the 
plate for the second time through the rolls a somewhat 
greater pressure is given, and the latter is finally increased 
to such an extent that on touching the plate with the 
fingers no elevation is noticed, this being proof of all the 
metallic particles having been sunk into the plate. The 
latter, when cold, is lightly ground and then highly 
polished. When such encrusted plates have to be bent, as 
is necessary, for instance, in the manufacture of cigar cases 
or pocket books, a metallic negative form has to be used. 
The celluloid plate is laid upon this form and sufficiently 
heated to allow of it being readily bent over it. 



CELLULOID. 301 

CELLULOID MOSAICS. 

An entirely original application of celluloid masses is 
their use for the production of mosaics equal in appearance 
to those of polished stones {pietra dura mosaics) chiefly made 
in Florence. 

Celluloid, as previously mentioned, may be colored any 
shade, and by filling it with colored powders, masses of any 
desired color may be produced. By coloring celluloid, for 
instance, blue with ultra-marine and pressing small laminae 
of mica into the colored mass, a body is obtained which 
bears a close resemblance to the valuable mineral known as 
lapis lazuli. By partly coloring white celluloid, imitations 
very true to nature of variegated marble may be obtained, 
etc. 

Celluloid plates thus colored may be used for the execu- 
tion of works of art closely resembling genuine Florentine 
mosaics, but, of course, costing much less to produce. Such 
mosaics are produced by cutting out by means of dies from 
the basis-plate of celluloid the portions which are to be filled 
in by differently-colored masses. With the same dies por- 
tions are then cut from colored celluloid plates, these por- 
tions, of course, fitting exactly into the empty spaces of the 
basis-plate. To prevent the celluloid plates from cracking 
while punching out the pieces, they are, previous to the 
operation, heated to between 12/*,° and 140° F. 

In executing the design a painted picture is followed, the 
celluloid pieces which have been cut from colored plates 
being placed in the proper empty spaces of the basis-plate, 
the latter resting upon a level zinc-plate. When the design 
has been executed, it is heated together with the support, 
till the celluloid becomes soft, and is then passed through 
rolls, by the pressure of which the firm union of all the 
celluloid pieces to a whole is efifected. The final finish is 
given to the plate by grinding and polishing. Before pol- 
ishing, the color effects of certain parts, where it appears 



302 CELLULOSE, AND CELLULOSE PRODUCTS. 

necessary, may be heightened by carefully painting them 
with tar colors dissolved in alcohol. 

As previously mentioned, such mosaic designs closely re- 
semble in appearance those made of differently-colored 
stones, but of course are much cheaper. 

CELLULOID LACQUER. 

A solution of nitro-cellulose and camphor in ether forms 
the substance which has in this work been repeatedly de- 
signated as celluloid solution, and to convert it into solid 
celluloid nothing has to be done but to allow the solvent to 
evaporate. If a solution of celluloid be poured upon a level 
glass plate in such a way that the thick fluid spreads in a 
thin layer over the glass plate, a thin plate of celluloid is 
obtained after the evaporation of the solvent, which may 
be used as so-called films for photographic purposes. 

By mixing celluloid solution with a suitable quantity of • 
strong alcohol, a fluid is obtained which dries more slowly 
upon the glass plate than the solution containing only 
ether, but leaves behind an exceedingly thin, though per- 
fectly homogeneous, film of celluloid. By dipping an 
article in this solution, or applying it with a brush, and 
allowing it to dry, an exceedingly thin coating of celluloid 
is formed, covering the entire surface of the article and pro- 
tecting it from the effects of dust and moisture, thus pos- 
sessing all the properties which may be demanded from an 
excellent quality of lacquer. 

No matter how thin such coatings of celluloid may be, 
they are perfectly water-proof, and even the most delicate' 
articles may be cleansed with a sponge and soap. The 
coating may be so thin as not to be noticeable, and if some- 
what thicker, imparts to the articles the beautiful lustre 
characteristic of celluloid. Thin coatings are especially of 
value for the protection of maps, copper and steel engrav- 
ings, as well as drawings in general. By coating both the 
face and back, of a map, water-color painting, or printed 



CELLULOID. 303 

sheet, with dilute celluloid solution and allowing the coat to 
dry, the paper is rendered almost indifferent to moisture. 
In case it has become dirty by frequent handling, it can 
without fear be cleansed by spreading it out upon a support 
and washing with a sponge and soap water, all the dirt 
adhering to the celluloid being thus removed without the 
underlying paper becoming even moist. 

A very thin layer of celluloid affords an excellent pro- 
tection for metals against rust, turning black and, in fact, 
against all external influences. Collections of armor, 
weapons, etc., have to be constantly watched to prevent 
-rusting. However, when once made bright and then pro- 
vided with a scarcely perceptible layer of celluloid, they 
retain their polish and need only from time to time be freed 
from dust by wiping with a woolen cloth, to be kept in 
perfect condition. Even if such articles are kept in a damp 
room, they show no trace of rust, the iron under the air- 
tight coating of celluloid being excluded from the action of 
moist air. 

The above-mentioned excellent properties of thin coat- 
ings of celluloid have led to the extensive use of celluloid 
solutions as lacquers. Numerous receipts for the prepara- 
tion of such lacquers have been published, some of them 
containing ingredients, the effect of which in the composi- 
tion is beyond comprehension. A detailed enumeration of 
.such receipts is here out of the question, and only the prin- 
ciples will be given according to which celluloid lacquers 
for various purposes have to be prepared, the main point 
being whether a lacquer yielding a strong, tenacious coat- 
ing is to be made, or one possessing a certain degree of 
flexibility and elasticity. 

The basis-material of all celluloid lacquers brought into 
commerce under various names, such as kristaline, zapon, 
victoria lacquer, etc., is nitro-cellulose of a composition re- 
presenting the soluble form. For the preparation of the 
various kinds of nitro-cellulose, the reader is referred to the 
detailed description given in a previous chapter. 



304 CELLULOSE, AND CELLULOSE PKODUCTS. 

An excellent celluloid lacquer may be prepared by 
simply dissolving nitro-cellulose and camphor in ether. 
However, by reason of the rapid evaporation of the ether, 
such a solution, when applied in thin layers, dries almost 
instantly, especially on a warm day, which is frequently 
inconvenient. It is, however, quite suitable for lacquering 
smaller articles by dipping, whirling off the excess of fluid, 
and swinging the articles for a few seconds to and fro, 
whereby they become perfectly dry, but it is not adapted 
for larger articles, as it dries almost under the brush. 

Celluloid lacquers are, therefore, best prepared with the 
use of a less volatile fluid, and, besides ether, quite a num- 
ber of solvents for nitro-cellulose, such as alcohol, acetone, 
potato fusel oil (amyl alcohol), benzine, etc., may be used 
for the purpose. 

The best results, as has been found, are obtained by 
using for the preparation of the solution a mixture of equal 
parts of pure ether and strong rectified alcohol, and by the 
process given below a lacquer is obtained which, as com- 
pared with other similar products, excels in clearness and 
lustre. 

The perfectly dry nitro-cellulose is weighed and brought 
together with the corresponding quantity of camphor — 2 
parts by weight of nitro-cellulose to 1 part by weight of 
camphor — into a wide-necked bottle, which can be closed 
air-tight with a well-fitting cork coated with paraffine. 
The lower end of the cork is furnished with a small hook 
for the suspension of a small bag of very close fine linen 
and made in the form of a sausage, which is filled with the 
nitro-cellulose. 

The camphor having been brought into the bottle, the 
mixture of equal parts of ether and alcohol is poured over 
it, and the bottle is frequently shaken till all the camphor 
is dissolved. The bag containing the nitro-cellulose is then 
suspended to the hook, the bottle closed air-tight with the 
cork, and placed where it is protected from shocks. The 



CELLULOID. 305 

nitro-cellulose at first swells up very much, and then grad- 
ually dissolves in the fluid, the linen bag acting as a filter, 
and retaining the portion of the nitro-cellulose which only 
swells up without dissolving. A perfectly clear solution is 
thus after some time obtained. 

The solution thus prepared is, as a rule, too thickly-fluid 
for direct use as a lacquer, but being miscible in every pro- 
portion with alcohol, a lacquer of any desired consistency 
can be readily obtained. 

When applied to an article, celluloid lacquer prepared 
according to the above-described process, yields a perfectly 
colorless coating. It may, however, be given any desired 
color by mixing the clear solution with a tar-color soluble 
in alcohol. A saturated solution of the coloring matter in 
alcohol is first prepared and filtered, and a sufficient quan- 
tity of it is added to the colorless lacquer to give it the 
desired shade of color. 

Very beautiful effects may be produced with colored 
celluloid lacquers especially upon paper and bright metals, 
and they can to advantage be used for lacquering fancy 
paper and small metal articles. Artificial flowers of paper 
when dipped in colored celluloid lacquer exhibit, after dry- 
ing, a very beautiful lustre and do not become unsightly 
by dust, the latter adhering only looselj'^ to the smooth 
coating and may be readil}^ blown off". Such flowers may 
even be cleansed by sprinkling them by means of an atom- 
izer with water until the pure color reappears. 

An important application of celluloid lacquers is for the 
conservation of metals. As previously mentioned, collec- 
tions of armor and weapons can in the simplest manner be 
protected from rust by a coating of celluloid, and metallic 
articles of every description may in the same manner be 
preserved, so that rasting becomes impossible, and for the 
purpose of cleansing they need only be wiped with a soft 
cloth. 

A coating of celluloid is said to be of special importance 
20 



306 CELLULOSE, AND CELLULOSE PKODUCTS, 

for metallic articles which come in contact with sea water. 
By reason of its content of salt, sea water acts very energet- 
ically upon metals, and constant cleaning and oiling are 
required to protect them from becoming rusty, but metal 
articles coated with celluloid lacquer remained bright when 
brought repeatedly in contact with sea water. The por- 
tions of iron vessels exposed to the action of sea water are, 
as is well known, strongly attacked, and it has been pro- 
posed to protect them by a coat of celluloid. While such a 
coat would, without doubt produce a favorable effect, a 
single application of thin celluloid lacquer would scarcely 
suffice. The use of a thickly-fluid lacquer would be re- 
quired, and several coats of it would have to be applied in 
order to fix upon the iron a layer of celluloid about 0.039 
inch thick, such a layer being of sufficient thickness not to 
be worn off", even after a long time, by the friction of the 
water. Special experiments in this direction are said to 
have been attended by excellent results, and it is claimed 
that no barnacles adhere to the smooth surface of the cellu- 
loid, as is otherwise the case. 

CELLULOID-LIKE MASSES WITHOUT AN ADDITION OF CAMPHOR. 

The pronounced odor of camphor of many articles pre- 
pared from celluloid is in many cases objectionable, and 
efforts have been made to substitute for the camphor other 
substances which, together with nitro-cellulose, would yield 
a product equal in physical properties to celluloid. 

To judge from the large number of substances proposed 
for this purpose, it may be supposed that either all of them 
yield with nitro-cellulose substances whose properties corre- 
spond with those of celluloid, or, what is more probable, 
that more favorable results are obtained with some of them 
than with others. 

According to a statement of the Societe generale pour la 
Fabrication des maiieres plastiques, the camphor in the man- 
ufacture of celluloid may be entirely replaced by naphtha- 



CELLULOID. 307 

line. However, the odor of naphthaline being still more 
intense and offensive to most people than camphor, the 
product obtained presents no other advantage over celluloid 
than that of being cheaper. 

Zuhl and Eisemann replace the camphor partly or en- 
tirely by a series of various bodies. They enumerate in 
their patent as suitable for this purpose : a and /? naphthyl 
acetate, phenoxyl or naphthoxyl acetic acids, their anhy- 
drides or esters, methylnaphthylketone, dinaphthylketone, 
methyloxynaphthylketone or dioxydinaphthylketone, and 
the esters of the oxanyl acids. By working up 25 kilo- 
grammes (55 lbs.) of oxanyl acid methyl ester either by 
itself, or together with a solvent, and 75 kilogrammes (165 
lbs.) of nitro-cellulose, a suitable product is obtained, as 
well as with the use of 30 kilogrammes (66 lbs.) of oxanyl 
acid, benzyl ester and 100 kilogrammes (220 lbs.) of nitro- 
cellulose. In place of camphor, according to the above 
mentioned authors, may also be used : triphenyl phosphate, 
tricresyl phosphate or trinaphthyl phosphate, or finally the 
monohalogen products of substitution of the aromatic 
hydrocarbons, so that camphor may be entirely banished 
from the manufacture of celluloid. 

J. R. Goldsmith uses in place of camphor, or as a partial 
substitute for it, acetodichlorhydrin, diacetochlorhydrin and 
monoacetomonochlorhydrin. 

According to a communication of the FarbwerJce, formerly 
Meister, Lucius and Briinig, the camphor in the manufac- 
ture of celluloid may be, either entirely or partly, replaced 
by aromatic sulpho-acids derivatives, derived from chlorides, 
esters and amides. Celluloid-like masses without camphor 
may be prepared with the use of neutral phtalic acid alkyl 
ester and phtalic acid alphyl ester. The following example 
may here be given : Dissolve 1000 parts of phtalic acid 
diphenyl ester in alcohol and add to the solution 2000 parts 
of nitro-cellulose. When the nitro-cellulose is completely 
swelled up, the mass is further worked in the usual way. 



308 CELLULOSE, AND CELLULOSE PRODUCTS. 

The corresponding cresyl ester of the above-mentioned 
bodies may in the same manner be used. 

The Deutsche Celluloid Fabrik at Leipzig-Plagwitz re- 
places camphor in the manufacture of celluloid by acetyl 
derivatives of secondary aromatic amines. 

No matter what substitute may be used for camphor in 
the manufacture of celluloid, practical success can be 
achieved only with a substance which yields a product, 
that, as regards transparency, elasticity and plasticity when 
heated, as well as capacity of being colored, corresponds 
with camphor-celluloid, and is entirely or nearly colorless, 
and can be produced at the same cost. 



XIII. 

RUBBER COMPOUNDS. 

By rubber compounds are understood masses consisting 
partly of rubber with the addition of other substances, these 
additions being generally made for the purpose of produc- 
ing a cheaper article, though in some cases also to impart 
to the rubber properties otherwise not possessed by it. 
From rubber alone, for instance, masses with properties 
like those of whalebone, especially as regards tenacity and 
elasticity, could not be produced, but it can be done with 
the use of suitable additions. 

The principal substances used as additions to rubber are 
resins — especially shellac — antimony pentasulphide or gold 
sulphur, and coal tar pitch. As indifferent filling sub- 
stances, any powdered materials insoluble in water may be 
used, for instance, chalc, ferric oxide (colcothar or rouge) 
or calcined magnesia. The use of the latter may be espe- 
cially recommended, because with great bulk, it has a com- 
paratively slight specific gravity, and articles filled with it 
are not conspicuous by great weight. 

Of the resins, shellac is most frequently used, it being 
harder and less brittle than other varieties, and for our pur- 
poses the dark-red article known in commerce as ruby sljel- 
lac is most suitable. 

Of the pitch-like substances, large quantities of the best 
grades of asphalt, as well as coal-tar pitch, are used as ad- 
ditions to rubber compounds. Asphalt combines readily 
with rubber, but has the disadvantage of a quite low melt" 
ing point, so that compounds containing a certain quantity 

(309) 



310 CELLULOSE, AND CELLULOSE PRODUCTS. 

of it, become soft at a comparatively low temperature and 
generally lose the greater portion of tlieir elasticity. 

Coal-tar pitch, large quantities of which are at present 
produced, is distinguished by having a much higher melt- 
ing point than asphalt, and besides yields compounds of 
considerably greater hardness, so that for this reason alone 
it is to be preferred. Coal-tar pitch is prepared by heating 
coal tar in a still until the greater portion of the volatile 
bodies is distilled over, and in the still remains a residue 
which, on cooling, congeals to a solid mass of a deep-black 
color. The last products of distillation escaping from the 
coal-tar pitch only at a temperature of more than 612° F., 
softening of the compound containing this pitch need not 
be feared. 

Manufacturers engaged in the preparation of rubber 
masses apply to their products various names, which gener- 
ally refer to some special property. Thus, masses possess- 
ing not much elasticity but a high degree of plasticity, are 
designated as plastite, while others distinguished by great 
tenacity and flexibility are known as artificial whalebone or 
balenite. Masses resembling in their properties and appear- 
ance ivory, are called ebonite, etc. 

PLASTITE MASSES. 

The compounds to which this term has been applied are 
frequently brought into commerce under the name of hard 
rubber. This designation is, however, misleading, genuine 
hard rubber consisting only of a mixture of rubber and sul- 
phur, which has been exposed to a suitably high tempera- 
ture. It is of a deep black color, quite hard, and neverthe- 
less possesses a considerable degree of elasticity. Plastite 
masses are also of a deep black color and are distinguished 
by considerable hardness, but instead of being elastic, are 
.quite brittle.) 

There are quite a number of receipts for the preparation 
of plastite masses. In some of them ingredients are given, 



RUBBER COMPOUNDS. 311 

the effect of which cannot in any manner be explained, 
and it may be supposed they have been introduced simply 
for the purpose of making the receipt appear as something 
new. 

A plastite mass possessing excellent properties has, accord- 
ing to Raimund Hoffer, the following composition : 

Kubber 100 parts by weight 

Sulphur 20 to 25 parts by weight, 

Magnesia 40 to 50 parts by weight, 

Pentasulphide of antimony 40 to 50 parts by weight. 

Coal-tar pitch 50 to 60 parts by weight 

The masses are prepared as follows : The rubber is 
worked by itself in the kneading machine till sufficiently 
soft, when the finely pulverized ingredients are added, and 
the whole is worked by mechanical means till a uniform 
mass results. The latter is then pressed under high pres- 
sure in iron moulds, and vulcanized in the same manner as 
hard rubber. The plastite thus obtained is of a deep black 
color, possesses considerable hardness, and takes a high 
polish. It is at present quite extensively used in the in- 
dustries, since a large number of articles which were form- 
erly made by hand from wood, metal, horn, etc., can be 
manufactured from it in a more simple, and therefore 
cheaper, way. 

ELASTIC RUBBER MASSES. 

With reference to their properties, elastic rubber masses 
are a medium between rubber vulcanized in the ordinary 
way and hard rubber, and by a suitable change in their 
quantitative compositions, they may be made either harder 
or more elastic. 

The chief requisites of masses of this kind are elasticity 
and tenacity equal to whalebone, and products are now 
prepared which, as regards these properties, answer all 
demands, and for many purposes have supplanted the gen- 
uine article. 



312 CELLULOSE, AND CELLULOSE PRODUCTS. 

A mass serving for the manufacture of balenite is com- 
posed of the following ingredients : 

Rubber 100 parts by weight. . 

Ruby shellac 20 parts by weight. 

Calcined magnesia 20 parts by weight. 

Sulphur 25 parts by weight. 

Pentasulphide of antimony 20 parts by weight. 

The ingredients are mixed in the same manner as given 
for plastite. However, the degree of elasticity and tenacity- 
depends to a great extent on the temperature at which vul- 
canizing is effected ; the lower the temperature the more 
elastic the finished mass will be, and the higher the tem- 
perature the more closely the product, as regards its proper- 
ties, will approach hard rubber. 

Balenite finds extensive application in the industries. It 
is, for instance, much used as a substitute for whalebone in 
the manufacture of corsets, it being even superior to the 
latter as regards flexibility. Suitably-shaped plates of it 
are used for arm and leg splints in surgery, and the bob- 
bins for cotton spinning are now largely made of it. On 
account of its light weight and indestructibility, it may be 
highly recommended for the manufacture of gunstocks. 

RUBBER-LEATHER. 

A product brought into commerce under this name, 
though possessing excellent qualities, has found but little 
application in the industries. As indicated by its name, it 
is claimed to have the properties of leather. However, as 
regards tenacity and durability, rubber-leather, like all such 
artificial products, cannot bear comparison with actual 
leather, though in quality it surpasses perhaps all prepara- 
tions of a similar character. As compared with actual 
leather it is distinguished by great flexibility and imperme- 
ability to moisture. 

Rubber-leather is prepared as follows : A rubber solution 
is first prepared, or a thick, mucilaginous and much-swollen 



RUBBER COMPOUNDS. 313 

mass by working rubber together with a solvent such as oil 
of turpentine or benzine. Waste fibres of all kind, such as 
flax, jute, hemp, etc., are then incorporated with the mass, 
it being sought to bring into it as many fibrous substances 
as possible. When the mass has finally acquired such con- 
sistency that it cannot be further worked between the rolls, 
it is stretched out into a long, thin band. This band is sev- 
eral times made into a lump which is again stretched out 
by rolling. By this repeated rolling, the fibres are piled in 
different directions, forming, so to say, a kind of felt. The 
mass is finally rolled into thin plates and allowed to lie in 
the air till the solvent has evaporated. 

In the rubber-leather thus obtained, the separate fibres 
are intimately cemented together by the rubber, and the 
material is distinguished by great tenacity. As shown by 
special experiments, a product of still greater tenacity is 
obtained by impregnating closely woven tissues of not too 
fine a quality with rubber emulsion, and uniting two or 
more such tissues by vigorous pressure. The product ob- 
tained in this manner, even if quite thin, possesses such 
tenacity as to be actually suitable for shoe uppers, carriage 
covers, etc. However, the cost of producing such materials 
is so high that they are more expensive than genuine 
leather, and this is very likely the chief reason why they 
have not been more generally introduced in practice. As 
mentioned in speaking of the various uses of viscose, tissues 
may now be made very tenacious and resisting by suitable 
treatment with thick viscose solutions, they being in every 
respect equal to tissues impregnated with rubber, but much 
cheaper. 

MARINE GLUE. 

This term is applied to a valuable rubber compound, 
which is of special importance when metallic articles com- 
ing alternately in contact with water and air are to be pro- 
tected from rust. 



314 CELLULOSE, AND CELLULOSE PRODUCTS, 

Marine glue is best prepared as follows : Small pieces of 
rubber are, by the application of heat, allowed to swell up 
in a quantity of anhydrous petroleum amounting to twelve 
times their weight. The mixture having been made uni- 
form by continued stirring and gentle heating, six times 
the quantity of ruby shellac or asphalt — or in place of the 
latter coal-tar pitch — is introduced. The mass is then 
made more thinly-fluid by stronger heating, and stirred till 
uniform throughout. 

For use, the marine glue is carefully melted and heated 
till thinly-fluid. The temperature required for this pur- 
pose being such as to exclude its application by means of 
bristle brushes, brushes of thin elastic wire are employed. 

By adding to the marine glue, while it is being prepared, 
a few per cent, of sulphur, and heating the articles coated 
with it to above 392° F., the mass is changed as is the case 
with all rubber compounds when heated to high tempera- 
tures ; the rubber is converted into hard rubber. Articles 
thus treated are actually coated with a thin, but flrmly ad- 
hering, layer of hard rubber, forming one of the most dur- 
able and resisting coats of lacquer known. 



XIV. 

RUBBER SUBSTITUTES. 

It is a well-known fact that the production of rubber does 
not keep up with its consumption. The constantly increas- 
ing demand for it cannot be met, and the price of it goes 
steadily up, though larger quantities than ever before are 
now brought into commerce from the Congo districts. 

This steadily increasing demand for rubber has also in- 
duced the chemist to seek for substances possessing proper- 
ties resembling those of rubber, but up to the present time 
none has been found, which equals it as regards elasticity, 
tenacity, chemical indifference, and insulating power for 
electricity. However, compounds possessing to a great ex- 
tent the above-mentioned properties are now successfully 
produced, and may for many purposes be substituted for 
rubber. By the invention of such masses great service has 
been rendered, especially to the electrical industry, because 
many of them possess the highly-important property of 
rubber, namely, the power of insulation. 

The rubber substitutes may be divided into two groups : 
Masses containing rubber, but only in subordinate quantity, 
while the main mass consists of other less valuable sub- 
stances ; and masses which contain no rubber whatever, but 
are prepared from various substances, and yield a product 
which may for many purposes replace rubber, thus repre- 
senting a rubber substitute in the actual sense of the word. 
According to Steenstrup's method, a material which may 
be utilized as a substitute for rubber is prepared as follows : 
Waste rubber is dissolved with the application of heat in 
drying oils. The resulting solution is strongly heated and, 

(315) 



316 CELLULOSE, AND CELLULOSE PRODUCTS. 

while constantly stirring, a current of air is conducted 
through it, till a cooled sample shows the proper consistency. 
Since the actual rubber substitutes, i. e., masses contain- 
ing no rubber whatever, deserve the greatest attention, be- 
cause no expensive materials have to be used in their 
production, they being on the contrary prepared from sub- 
stances, large quantities of which are always at disposal, a 
more detailed description of them will here be given. They 
are prepared by a peculiar treatment of oils, and according 
to their mode of production may be designated : 1. Oxi- 
dized oils. 2. Sulphured oils. 3. Oils treated with disul- 
phur dichloride. By treatment with the chemicals, the- 
oils, in all cases, undergo such far-reaching chemical 
changes that they cannot be called changed oils, but must 
be designated as products formed from the oils. The gen- 
eral term oil-rubber has been applied to these products, but 
they may be divided into several subdivisions, namely : 
Actual oil-rubber, vulcanized oil, andfactis. 

OIL-RUBBER, 

Certain oils possess the property of absorbing in the 
course of time, when exposed to the air, considerable quan- 
tities of oxygen, becoming thereby thicker, and are finally 
converted into quite solid masses, which, however, retain 
always a certain elasticity. Such oils are called drying oils^ 
in contra-distinction to non-drying oils, which turn rancid 
on exposure to air, but remain thinly-fluid. The best 
known representative of the drying oils is linseed oil, and 
of the non-dr3dng oils, olive oil. 

By raising the temperature the oxidizing action of the 
oxygen is considerably increased, and with the use of 
higher temperatures, linseed oil may in a comparatively 
short time be completely oxidized. This fact, together 
with the powerful oxidizing action of nitric acid, is ex- 
tensively made use of in preparing oil-rubber. 

The first step in the manufacture of oil-rubber is to bring 



HUBBER SUBSTITUTES. 317 

the linseed oil into large boilers, preferably heated by gas 
supplied from a generator-furnace, instead of by an open 
fire. With the use of generator-gas, the temperature to 
which the boiler is to be heated can be most accurately 
regulated, and there is no danger of its contents running 
over or igniting, which would cause considerable loss. 

In the generator-furnace furnishing the gas lies a wrought 
iron pipe, one end of which is connected with an air-forcing 
pump, while the other end, close over the bottom of the 
boiler, terminates in a rose resembling that of a watering 
pot. 

The operation is commenced by heating the linseed oil in 
the boiler nearly to the temperature at which decomposi- 
tion commences, but without ever reaching that point. 
When the linseed oil commences to throw out thick vapors 
and gets into an undulating motion, resembling that of a 
boiling fluid, its consistency has already undergone a re- 
markable change. While before, the oil would run down 
in a thin stream on a spatula dipped into it, it now shows 
quite a high degree of viscosity, and runs from the spatula 
in viscous, thick drops. 

When the oil has reached this state, the air-pump is set 
to work and a current of hot air is uninterruptedly forced 
through the oil. In contact with the hot air oxidation pro- 
ceeds very rapidly, and heating for three to five hours is 
generally sufficient for the conversion of the oil into a 
viscous mass. 

In order to ascertain whether the oil has been sufficiently 
heated, a sample is taken from the boiler and allowed to 
oool rapidly upon a metal plate. The drops of oil should 
at the ordinary temperature congeal to the consistency of 
hardening glue, and show elasticity when pressed with the 
point of the finger. 

When the sample is of suitable consistency, the oil is 
brought into iron vats in which it remains till cooled to the 
ordinary temperature, and is then further worked. The oil 



318 CELLULOSE, AND CELLULOSE PRODUCTS. 

might be allowed to cool in the boiler itself, but this would 
require too much time, and besides the boiler could not be 
immediately used for a fresh operation. 

The final oxidation of the oil is effected by treating it 
with nitric acid, the quantity of acid required being the 
smaller the further the oxidation of the oil in the boiler has 
been carried. Hence, a fixed proportion of oil to acid can- 
not be given, and the quantity of the latter required for the 
contents of the boiler has to be determined by an experi- 
ment on a small scale. 

The thick oil is brought into large stoneware or porcelain 
dishes which will bear heating, and the required quantity of 
nitric acid having been added, the mass is heated, and 
frequently stirred with a glass rod. By the powerful oxi- 
dizing action of the nitric acid, the oil thickens very rapidly 
and samples have to be repeatedly taken. When a sample 
cooled to the ordinary temperature appears quite solid and 
can be readily kneaded with the fingers, the action of the 
nitric acid is finished. It is of importance to place the 
dishes in which the thick oil is to be heated with nitric 
acid in a room which can be thoroughly aired, considerable 
quantities of nitric oxide being evolved by the action of the 
nitric acid upon the linseed oil. This gas, as is well known, 
exerts an injurious effect upon the respiratory organs, and 
should, therefore, by all means be removed from the work- 
room. 

When reaction is complete, the mass is allowed to cool to 
the ordinary temperature in the dishes, and is then rolled 
into thin bands by passing it through two glass rolls very 
closely set together. The band thus formed is allowed to 
drop into a large vessel filled with warm water, the greater 
portion of nitric acid adhering to it being thereby removed. 
For the purpose of freeing it from the last traces of acid, it 
is thoroughly worked in a large vessel containing hot soda 
solution. 

The oil-rubber obtained in this manner forms a brown, 



RUBBER SUBSTITUTES. 319 

elastic mass possessing quite a high degree of elasticity. It 
is indifferent towards most chemicals, and is not changed 
by remaining for a long time under water. It dissolves 
with ease in oil of turpentine, and this behavior may be 
utilized to increase its elasticity, or to incorporate indif- 
ferent substances with it, by adding small quantities of oil 
of turpentine to the mass while it is being worked in the 
rolls. In the course of time, oil-rubber loses some of its 
elasticity, the latter decreasing also to a considerable extent 
at a lower temperature. Old oil-rubber which has become 
hard, may however, be restored by cutting it up into small 
pieces, bringing the latter into a vessel, sprinkling oil of 
turpentine over them, and closing the vessel air-tight. The 
mass in a short time swells up in the oil of turpentine, and 
by kneading can be made into a uniform substance with 
nearly the same properties as freshly-prepared oil-rubber. 

Oil-rubber may for many purposes be used as an excellent 
substitute for genuine rubber. Thus, for instance, it is very 
well adapted for cushions for the support of rapidly-revolv- 
ing machinery to neutralize the shocks to which its parts 
are exposed. It is, however, especially suitable as an in- 
sulating material for electric lines, and, in a softened state, 
is much used for covering electric wires. 

MANUFACTURE ON A LARGE SCALE OF OIL-RUBBER BY MEANS 
OF THICK OIL. 

In the manufacture of oil-rubber, as well as in the pro- 
duction of other materials used as rubber substitutes, the 
linseed oil used for the purpose has by long-continued heat- 
ing to be highly oxidized till it is converted into a viscous 
mass. For the purpose of obtaining such a mass, the lin- 
seed oil has, however, to be heated for a comparatively long 
time at a temperature closely approaching that at which 
decomposition begins. 

This operation is, however, not only expensive, but also 
to a certain extent dangerous — expensive by reason of the 



320 



CELLULOSE, AND CELLULOSE PRODUCTS. 



considerable consumption of fuel, and dangerous on account 
of the ease with which the heated oil ignites, and of the 
vapors evolved from it, which attack the eyes and respi- 
ratory organs. 

Since oxidation can evidently take place only where the 
hot oil is in contact with air, i. e., on the surface, when 
heating is effected in boilers, oxidation can, of course, be 
accelerated by giving the oil a very large surface. For 

Fig. 40. 




the purpose of attaining this object various apparatuses 
have been constructed, the main feature of which consists 
in that the oil falls down in the form of a spray, and is met 
by an ascending current of warm air. Fig. 40 shows an 
apparatus which answers these demands. 

The oil to be worked is poured through the aperture 
on the boiler-shaped vessel L, and is then closed. The 



RUBBER SUBSTITUTES. 321 

vessel L is surrounded by a jacket M. The oil is heated 
by opening the cock D, and introducing steam in the space 
between L and if, the condensed water running off through 
E. In the vessel L lies a pipe rolled into a spiral, which 
rises free in the centre of the vessel, and is covered by a 
sheet-iron cap H. The end V of the spiral pipe projecting 
from L is connected with a ventilator which constantly 
forces a slow current of air through the pipe S. In its pas- 
sage through this pipe, the air is heated and escapes at H. 
Upon the vessel L sits a box several meters high. The 
sides of this vessel are of glass, so that the oil falling down 
into the box, is exposed to the action of the warm current 
of air, as well as to that of light, its oxidation being in a 
very short time effected by both of these factors. The oil 
is constantly sucked by a pump from L, and forced through 
the pipe R into the reservoir B. The latter is furnished 
with a perforated bottom, so that the oil divided into fine 
drops falls free through the space C, and meets the ascend- 
ing warm current of air, which escapes from the box GG 
through the apertures at T. 

As a rule, two to three hours suffice to thicken the oil in 
this apparatus to the same consistency it would otherwise 
acquire by long-continued heating to a very high tempera- 
ture. In addition, this mode of preparing thick oil, has 
tlie advantage of the product retaining its light color, while 
oil thickened by long-continued heating always acquires a 
dark-brown color. 

The thick oil is worked as follows : It is brought into a 
large stoneware or porcelain dish, and nitric acid diluted 
with about twice its volume of water having been poured 
over it, the whole is heated to the boiling point. The 
linseed oil mass becomes thereby constantly thicker, and 
finally solid. Boiling is continued until a sample, when 
cold, scarcely takes the impress of a finger nail. 

When this is the case, the mass is taken from the nitric 
acid and, for the removal of the last traces of the latter, is 
21 



322 CELLULOSE, AND CELLULOSE PRODUCTS. 

repeatedly boiled in water. If the mass is to be brought 
into any particular shape, it need only be placed in hot 
water, becoming thereby perfectl}' plastic and, on cooling, 
reacquires its original solidit}' and elasticity. 

Oil-rubber may be applied to various purposes, and in 
many cases serve as a substitute for rubber. Its use for 
securing large panes of glass in frames might prove of 
special importance and value. While ordinary putty, in 
the course of time, becomes hard as stone, oil-rubber always 
remains elastic, and allows of the expansion of the glass in 
sudden changes of temperature, cracking of the glass being 
thus prevented. Oil-rubber being quite tenacious, it might 
also be suitable for tires for heavy wagons and motor 
wagons. When softened by heating it may readily be 
rolled out into thin plates which, when applied by pressure 
to tissues, adhere firmly to them and render them w^ater- 
proof. 

FACTIS MASSES. 

Under the name /adts, masses have for some time been 
brought into commerce from England, which may be used 
as a direct substitute for rubber, as well as an addition to 
pure rubber, the essential properties of the latter being not 
perceptibly impaired by the admixture of quite a consider- 
able quantity of them. Factis masses vary very much in 
appearance, some of them being of a white, or only slightly 
yellowish, color, while others are more or less dark brown 
to black. Their consistency is similar to that of quite 
highly vulcanized rubber. 

The result of a chemical examination makes it quite cer- 
tain that these masses are prepared from a fat oil, and in 
all of them considerable quantities of sulphur were found, 
while some of them also contained considerable quantities 
of chlorine. Based upon these examinations, it was sur- 
mised that the factis masses are prepared either from sul- 
phured oils alone, or that they may also be produced by a 



RUBBER SUBSTITUTES. 323 

reaction of disulphur dichloride upon fat oils. Both these 
surmises proved correct, and the production of factis equal, 
as regards properties, to the English article, has been suc- 
cessfully accomplished. 

SULPHURED OILS (BROWN AND BLACK FACTIs). 

Drying as well as non-drying fat oils, when heated to- 
gether with sulphur dissolve a considerable quantity of the 
latter, being thereby converted into viscous masses of a 
dark color. If the oil, previous to the introduction of the 
sulphur, be highly oxidized, solid, tenacious, and, up to a 
certain degree, elastic masses of a dark brown to black 
color are obtained. 

Every kind of fat oil may be used for the production of 
such masses, though castor oil and rape oil are said to be 
most suitable for the purpose. The oils may be used in 
the crude (unrefined) state, the admixed foreign substances, 
such as mucilage, albumen, etc., being separated during the 
manipulation. 

A weighed quantity of oil is brought into a capacious 
boiler and quickly heated to about 392° F. The oil rising 
very much in the boiler, the latter should only be filled at 
the utmost two-thirds full. By heating, considerable quan- 
tities of frothy curd are separated upon the surface of the 
oil and have to be removed, so that the oil appears as a 
lustrous, black mass. During the process of heating a cur- 
rent of hot air is forced through the oil till a cooled sample 
shows a considerable degree of viscosity. 

The sulphur to be used should be perfectly free from sul- 
phurous acid. Hence, flowers of sulphur must previously 
be thoroughly washed and again dried, and roll-sulphur, if 
used, has to be reduced to a fine powder. 

Five parts of oil to 1 part of sulphur are used. An ex- 
cess of the latter should be avoided, as it would not be dis- 
solved in the mass, but simply distributed in it. The 
sulphur powder is allowed to run without interruption in a 



324 CELLULOSE, AND CELLULOSE PRODUCTS. 

thin jet into the hot oil, the latter being kept in constant 
motion by means of a paddle, or what is better, by a me- 
chanical stirrer. Shortly after the introduction of the 
sulphur, the mass commences to rise very much, and a too 
vigorous reaction has to be prevented by moderating the 
fire and by vigorous stirring. 

The operation ma}'^ be considered finished when a sample 
of the mass dropped upon a cold sheet of metal congeals to 
a solid body. The contents of the boiler are then brought 
into shallow, prismatic sheet-iron vessels, and allowed to 
congeal. The mass, while still warm, is taken from the 
vessels, and made uniform by rolling. It is finally again 
softened by the application of heat, and made into blocks 
by pressure. 

This oil-rubber is less often used by itself, but finds 
considerable application as an addition to rubber for the 
manufacture of cheaper articles. 

Several other substances, chiefly asphalt and vaseline, 
are frequently added to oil-rubber masses, which are not 
to be mixed with pure rubber. When vaseline is to be 
used, it is added to the oil when the latter is heated, and, 
when melted, intimately mixed with it by stirring. The 
mixture is then treated with hot air in the above-described 
manner. If asphalt is to be incorporated with the mass, 
it is added in small pieces to the hot oil and intimately 
mixed with it by stirring. A quantity of asphalt equal to 
10 per cent, of the oil may be added. 

Masses of a dark brown to black color are finally obtained. 
They may be used by themselves as an insulating material 
for electrical purposes, though they are chiefly utilized as 
an addition to rubber. 

VULCANIZED OIL. 

The product to which this term has been applied is 
formed by the action of disulphur dichloride upon oils. 
If a fat oil, for instance, rape oil, be mixed with a quan- 



RUBBER SUBSTITUTES. 325 

tity of disulphur dichloride equal to yV of its volume, the 
latter at first dissolves without perceptible change. How- 
ever, a very energetic reaction soon sets in. The mass be- 
comes heated to between 131° and 140° F., evolves vapors 
of hydrochloric acid, and is converted into a solid trans- 
parent substance which, when brought into water, becomes 
opaque and possesses the consistency of rubber. 

While oil-rubber is soluble in oil of turpentine, alkalies, 
etc., vulcanized oil is distinguished by its great indifference 
towards the action of chemicals, being not affected even 
by boiling alkalies and acids. 

This indifference may be utilized for the preparation of a 
varnish possessing great power of resisting the action of 
chemicals. Dissolve linseed oil in a quantity of carbon 
disulphide equal to 30 or 40 times its weight, add disulphur 
dichloride equal to j\ of the weight of linseed oil, and use 
the mass for coating wood, tissues, metals, etc. The coat 
becomes dry in a few days, when the article appears as 
having been coated with vulcanized oil. 

WHITE FACTIS. 

This product occurs in the form of yellowish-white elastic 
masses possessing a slight odor of oil. It is not attacked 
by dilute alkalies and acids. It is produced by the action 
of disulphur dichloride upon fat oils, and it is a remarkable 
fact that exactly determined quantities of disulphur di- 
chloride have to be used. If smaller quantities of it are 
taken the oils are only converted into smeary, gelatinous 
masses, which never become solid. 

R. Henriquez has devoted much time to the investigation 
of rubber substitutes, and to him we are indebted for the 
correct method of preparing white factis. 

If a fat oil be compounded with a sufficiently large quan- 
tity of disulphur dichloride, a mixture of the two fluids is 
immediately effected. However, the fluid in a short time 
becomes heated, rises in bubbles, evolves vapors, and is in 



326 CELLULOSE, AND CELLULOSE PRODUCTS. 

a short time converted into a pale-yellow, solid substance, 
showing scarcely any stickiness or elasticity. The vapors 
evolved consist chiefly of disulphur dichloride mixed with 
small quantities of hydrochloric acid and sulphurous acid. 
By exposure to the air a small quantity of disulphur di- 
chloride evaporates, and the mass then possesses all the 
properties of the English product. 

Dilution of the disulphur dichloride with benzine or 
carbon disulphide causes the reaction to run its course less 
violently, but the final product is the same as with the use 
of pure disulphur dichloride. 

Drying, as well as non-drying oils, may be utilized for 
the production of factis, and, strange to say, the quantities 
of disulphur dichloride required for the conversion of the 
different oils into factis vary very much. As shown by 
comparative experiments, oxidized oils, i. e., oils which 
have been thickened by blowing hot air through them, re- 
quire far less disulphur dichloride for the formation of 
factis than oils not treated in this manner. Oxidized cot- 
ton oil yielded a good quality of factis with 20 per cent, of 
its weight of disulphur dichloride, while 40 per cent, was 
required for non-oxidized oil. The figures given below for 
some of the oils most frequently used for the production of 
factis, as compiled by Henriquez, refer to non-oxidized oils : 

100 parts congeal 

Linseed oil . . with 30 parts disulphur dichloride but not with 25 parts. 

Poppy oil. . . "35 " " " " " " 30 " 

Rape oil ... " 25 " " " " " " 20 " 

Cotton oil . . . " 45 " " " " " " 40 " 

Olive oil ..." 25 " " " " " " 20 " 

Castor oil. . . "20 " " " " " " 18 " 

The manner of preparing factis on a large scale is to 
some extent indicated by what has been said above. Di- 
sulphur dichloride being an expensive article, it would for 
economical reasons seem advisable to work with oxidized 
oils, they requiring less of it than non-oxidized oils. 



RUBBER SUBSTITUTES. 327 

Special vessels of a shape suitable for the purpose should 
be used for the oxidation of the oil, a shallow pan, upon the 
bottom of 'which lies a bent pipe furnished with numerous 
narrow apertures by means of which hot air is blown 
through the oil being very suitable. The crude oil having 
been rapidly heated to between 392° and 464° F,, and the 
scum removed from the surface, a current of hot air is 
blown through it, whereby the temperature may be in- 
creased to about 572° F. When the oil is sufficiently thick- 
ened, it is allowed to run in a thin jet into the reservoir, 
and to cool in it to the ordinary temperature. The prepar- 
ation of factis is, as a rule, effected in deep boilers enam- 
elled inside, having each a capacity of up to 66 gallons. 
However, only about 110 lbs. of oil should at one time be 
worked, since the oil on coming in contact with the disul- 
phur dichloride rises in the boiler, and with larger quanti- 
ties, reaction would be so violent that running-over of the 
mass could scarcely be avoided. The boilers should be so 
arranged in the workroom that over each of them is fixed 
a hood of boards for catching the vapors, the latter being 
rapidly removed by means of a powerful ventilator. This 
precaution is absolutely necessary, as disulphur dichloride 
is very poisonous and attacks especially the respiratory 
organs. 

The weighed quantity of oil is brought into the boiler 
and by vigorous stirring set in a rapid rotatory motion, 
when the required quantity of disulphur dichloride is al- 
lowed to run in, stirring being continued so long as the 
consistency of the mass will permit. The commencement 
of the reaction is indicated b}^ the appearance of white 
vapors, and the end of it, by the cessation of the evolution 
of vapors, when the mass must at the same time have be- 
come solid. 

The mass is now quickly taken from the boiler and rolled 
out into thin bands. The latter are placed on nets made 
of twine stretched in frames, where they remain until the 



328 CELLULOSE, AND CELLULOSE PRODUCTS. 

odor of disulphur dichloride has entirely disappeared. The 
mass should be entirely odorless, or only show a slight odor 
of oil. It should not yield soluble bodies of any kind to 
water. By heating, it must become soft and plastic, and 
allow of its being rolled or pressed into any desired shape. 
By themselves, factis masses prepared from oils with disul- 
phur dichloride may be very well used for insulating elec- 
tric lines, but their principal application is as admixture to 
genuine rubber, it being thus possible to bring into com- 
merce cheaper rubber articles. The addition of factis is 
generally effected while working the crude rubber in the 
kneading machine, the whole being worked until a thor- 
oughly homogeneous mass has been formed, in which the 
particles of rubber cannot be distinguished from the par- 
ticles of factis. 

SULPHURETTED HYDRO-CELLULOSE AS RUBBER SUBSTITUTE. 

A substitute for pure rubber, which may be prepared 
with the use of sulphuretted hydro-cellulose, discovered by 
Sthamer, deserves special attention. This compound is 
obtained by bringing 440 lbs. of finely ground hydro-cellu- 
lose into a sufficient quantity of hydrochloric acid of 24° Be., 
at the ordinary temperature, so that a thin paste is formed 
and all is dissolved. To the solution 154 lbs. of disulphur 
dichloride are added, with vigorous stirring. The fluid 
after some time becomes turbid and acquires a gray-yellow 
color. By bringing later on the entire mass into cold 
water, the sulphuretted hydro-cellulose in the form of a 
mass, insoluble in water, separates upon the bottom of the 
vessel. It is brought upon a filter to recover as far as pos- 
sible the hydrochloric acid, the acid running off first, still 
showing a strength of 20° B^. Later on the mass is washed 
with water until the fluid running off no longer shows an 
acid reaction. 

Pure sulpho-hydrocellulose is very indifferent towards 
chemicals, and cannot be dissolved in any known solvent. 



RUBBER SUBSTITUTES. 329 

It appears that the combination may to great advantage be 
utilized in the rubber industry for the preparation of a very 
good, and at the same time cheap, substitute for rubber. 
By heating the sulpho-hydrocelhilose together with rubber, 
it is decomposed, and yields the entire quantity of sulphur 
contained in it to the rubber, the latter becoming thereby 
vulcanized. The liberated cellulose at the same time en- 
ters into chemical combination with the entire mass, the 
result being a thoroughly uniform body. 

By mixing sulpho-hydrocellulose — about 60 per cent. — 
with inferior qualities of rubber, and heating, more or less 
porous masses are obtained, from which tubes and plates 
suitable for insulating electric lines may be formed. In a 
moist state, sulpho-hydrocellulose may also be pressed in 
moulds. The articles thus obtained, when dry, are very 
hard, of a greasy feel, slight lustre, and should possess the 
color of wood. 

PREPARATION OF DISULPHUR DICHLORIDE. 

Large quantities of disulphur dichloride are used in the 
manufacture of vulcanized oil and factis masses, and being 
rather expensive, it is of advantage to manufacturers of 
these materials to prepare it themselves. 

Disulphur dichloride is obtained by heating sulphur and 
passing dry chlorine gas over it. The sulphur melts, and 
the two elements unite to a volatile combination of the 
composition SgClj. For the preparation of large quantities 
of disulphur dichloride, the apparatus shown in Fig. 41 
may be used. It consists of the glazed stoneware muffle 
M, placed in the furnace F, so as to be uniformly heated on 
every side. On top of the muffle is a pipe R, projecting 
above the furnace, through which the sulphur to be worked 
is introduced. During the operation this pipe is closed by 
a lid luted with clay. The pipe C, the end of which is 
slightly bent downwards, connects with the apparatus for 
the development of the chlorine gas, and enters the muffle 



330 



CELLULOSE, AND CELLULOSE PRODUCTS. 



through the back wall. The pipe D placed in the front 
wall of the muffle terminates in a cooling coil, in which the 
vapors evolved in the muffle are condensed. 

The operation commences with melting the sulphur in 
the muffle and heating it to between 320° and 338° F., 
when the chlorine gas is introduced. The latter, before 
reaching the muffle, must pass through a vessel filled with 
concentrated sulphuric acid, in order to free it from every 
trace of moisture. The fire as well as the current of 
chlorine gas is so regulated that the crude disulphur di- 
chloride runs off in a uniform stream from the cooling coil. 

Fig. 41. 




The fluid obtained in this manner is by no means a pure 
product, it containing considerable quantities of sulphur in 
solution. However, it may be directly used for the prepar- 
ation of factis, the presence of sulphur in it not having 
proved detrimental. 

For the purpose of obtaining pure disulphur dichloride, 
suchfas is required for experiments, the crude product is 
repeatedly distilled from glass retorts until a distillate boil- 
ing at 266° F. and of specific gravity 1.6802, is obtained. 
The pure disulphur dichloride thus prepared is an oily, red- 
yellow liquid, fuming strongly in the air, it being, by the 



RUBBER SUBSTITUTES. 331 

moisture contained in the air, immediately decomposed to 
sulphur dioxide, sulphurous acid, sulphur and hj'^drochloric 
acid. The vessels serving for storing disulphur dichloride 
must, therefore, be carefully dried and closed air-tight with 
ground-glass stoppers. 

Great care should be exercised in handling disulphur di- 
chloride, the mucous membranes of the eyes, nose and 
respiratory organs being violently attacked by the vapors 
of it. The best protection from the vapors for the work- 
man engaged in mixing the disulphur dichloride with the 
oil, is a head-piece or mask, air from the outside being in- 
troduced through a hose connected with an air-pump. 



INDEX. 



ABADIE'S grinding machine, 32, 
33 



Acetic acid, 126 

action of, upon cellulose, 13 
concentrated, use of, for dis- 
solving nitro-cellulose, 223 
Acetone, treatment of nitro-cellulose 

with, 189 
Acetyl-cellulose, 202, 203 

derivative of cellulose, 202, 203 
lactic acid, 126 
Acid for nitration, 175-177 

sulphites of alkalies and alkaline 
earths, action of, upon cellu- 
lose, 13 
Acids, behavior of cellulose towards, 
11-14 
storage of, 176 
After-nitration, 181 
Alcohol, absolute, boiling-point of, 274 
and sugar, production of, from 

wood cellulose, 93-107 
behavior of celluloid towards, 282 
from beech, 96 
cellulose, 12 
wood, 12 

apparatus for the produc- 
tion of, 97 
Classen's process, 102- 

107 
value of, 102 
nature of wood to be worked for, 

96-98 
solidification of, 203, 204 
varieties of wood suitable for the 

production of, 97 
yield of, from wood, 107 
Alcoholic camphor solution, prepara- 
tion of celluloid with, 269, 270 
Alkalies, behavior of cellulose towards, 
14, 15 
caustic, treatment of cellulose 
with, 14, 15 
Aloe, 6 

Ammonia, replacing the soda in vis- 
cose by, 131 
J^mmonium sulphate, recovery of, 241 

(333) 



Ammonium sulphide, denitration 
with, 220 
viscose, use of for sizing paper, 
139, 140 
Amyloid, 12 

Animals, occurrence of cellulose in, 2 
Antimony pentasulphide, 309 
Aqua regia, use of, for the disintegra- 
tion of the wood-fibre, 51 
Armor, celluloid lacquer for, 303 
Artificial flowers, celluloid lacquer for, 
305 
horse-hair, 244, 245 
rubber, 197-200 
silk, 171, 205-228 

according to M. Fremery and 

J. Urban, 242-244 
apparatus for spinning, 217- 

219 
bleaching of, 221 
Bronnert's, 236, 237 
Chardonnet, 209-222 
colored, preparation of, 221, 

222 
denitration of, 220, 221, 225- 

228 
Du Vivier's, 222-224 
industry, historical develop- 
ment of, 207-209 
Lehner's, 224, 225 
Miller's, 253, 254 
Pauly's, 230-236 
Peit's, 227 
Art objects from celluloid, 300 
Asbestus-felt filtering plates, 233 



BACHET and Machard's method, 
51, 52, 95 
Balenite, composition of, 312 
Bark, machine for removal of, 24, 25 
Battery for lixiviation, 57 
Beater, reduction of gun-cotton in the, 

184, 185 
Beech, production of alcohol from, 96 
steaming of, 43, 44 
yield of cellulose from, 59 
Belts for machines, 150 



334 



INDEX. 



Berlin-blue on celluloid, 286 

Bevan, Beadle and Cross, invention of 

viscose and viscoid by, 119 
Billiard balls, 159 
Birch, yield of cellulose from, 59 
Black factis, 323, 324 

on celluloid, 286, 287 
Bleaching agents for pulp, 43 

artificial silk, 221 
Blue on celluloid, 286 

vitriol, 237 
Board machine, 40 
Boards from steamed wood-pulp, 47, 48 

preparation of, 40 
Boiler for boiling straw, 76, 77 

wood with lye, 67, 68 

Sinclair's, 54, 55 
Boiling process, Ungerer" s, 55 

wood under pressure, 98, 99 
Boll of cotton, 4 

Bronnert's artificial silk, 236, 237 
Brown factis, 323, 324 

on celluloid, 286 
Butts, use of, 78 

CADORET'S method of preparing 
artificial silk, 208 
Calcium bisulphite, preparation of, 61 

test for, 69, 70 
Camphor and collodion-cotton, ap- 
paratus for dissolving, 273 
celluloid masses without an addi- 
tion of, 306-308 
mixture of, with collodion-cotton, 

267 
solution, alcoholic, preparation of 

celluloid with, 269, 270 
substitutes for, 307, 308 
Cane heads from celluloid, 290 
Carbon disulphide, 126 

and soda-lye, proportion 

between, 127 
protection of the workmen 

from the vapors of, 148 
recovery of, 1 28, 148 
use of, in the preparation 
of viscose and viscoid, 119 
Carton pierre, 16 
Castor oil, 316 

addition of, to nitro-cellulose, 
197 
Celloidin, 194 
Celluloid, 17, 263-308 

admixture of foreign bodies with, 

268 
apparatus for the preparation of, 

267 
articles, moulding of, 293-295 
pictures on, 287-289 



Celluloid, artificial flowers of, 152 
behavior of, towards solvents, 282 
chemical nature of, 263 
cliches from, 295, 296 
collars and cuffs, 297, 298 
coloring of, 284-287 

with cinnabar, 299 
combs, manufacture of, 295 
constituents of, 268 
constitution of, 263, 264 
drying chamber for, 279, 280 
dry method for the preparation 

of. 265 
elasticity of, 282, 283 
films of, 153 

for dentist's use, 298, 299 
for surgical purposes, 282 
inflammability of, 281, 282 
joining two pieces of, 294, 295 
lacquer, 302-306 

colored, 305 
masses, heating apparatus for, 
293, 294 
without an addition of 
camphor, 306-308 
mechanical manipulation of, 283, 

284 
methods for the preparation of, 

263, 264 
mixing of, with filling materials, 

290, 291 
mosaics, 301, 302 
physical properties of, 282 
plasticity of, 281 
-plate, preparation of for printing, 

287 
preparation of, according to Hyatt, 
266-268 
of, according to Mag- 
nus, 270, 271 
of, according to Tribou- 
illet and Besancele, 
268, 269 
of, with alcoholic cam- 
phor solution, 269, 
270 
of, with recovery of 
the solvent, 271-279 
principal requisite for the manu- 
facture of, 265 
printing on, 287-289 
properties of, 280-283 
rolling of, 280, 283, 284 
shaping of, by pressing, 295 
solid, preparation of, 277-279 
stamps, 296 
trays for the solidification of, 275, 

276 
tubes, 294 



INDEX. 



335 



Celluloid, wet methods for the pre- 
paration of, 265 
with filling materials, 289-293 

incrustations, 300 
working of, 283, 284 
Cellulose, 1-21 

acetic ester, 200-203 
acetyl derivative of, 202, 203 
alcohol from, 12 

and caustic soda, quantitative 
proportions of, 122 
nitro-cellulose silks, differ- 
ence between, 261 
soda, combination of, 119 
artificial silk and lustra-cellulose, 

229-245 
behavior of, at an increased tem- 
perature, 15. 16 
towards acids, 11-14 
alkalies, 14, 15 
water, 8, 9 
black particles in, 72 
bleaching of, 239, 240 
brown bundles of fibre in, 72 
butyric ester, 203 
chemically pure, preparation of, 

from cotton, 6 
combinations formed by the action 

of nitric acid upon, 161 
comminution of, 122 
conversion of, into fermentable 

sugar, 17 
defects of, and their removal, 72, 

73 
destructive distillation of, 15 
digestibility of, 7 
dinitrate. 195 
distribution of, 1 
effect of sulphuric acid on, 82 
esters, 200-204 
filtering plates, 249 
formula of, 6 
for the preparation of viscose, 

121, 122 
from straw, 18, 19, 75-78 
wood, 3 

preparation of, 50-81 
principal point in (he 
preparation of, 50, 51 
hexanitrate, 194 

historical development of the pro- 
duction of. 20, 21 
industrial uses of, 16, 17 
iron in, 73 
occurrence of, 2, 3 
pentanitrate, 194 
percentage composition of, 7 
preparation of, bv means of soda, 
52-59 



Cellulose, preparation of, by means of 
sodium sulphite, 58, 59 
of, from straw, 2, 3 
of oxalic acid from, 108- 

118 
of, with the assistance of 

sulphites, 59-73 
of, with the assistance of 
the electric current, 
73-75 
production of, 17-21 

of sugar and alcohol from, 
93-107 
properties of, 6, 7 
pure, from viscose, 246 
readily soluble, preparation of, 240 
separation of, 234 
silk, 206 

small, lustrous crystals in, 72, 73 
solubility of, 78 
solvents for, 8, 229 
sources of, 17, 18 
sulphocarbonate, 126, 127 

chemically pure, preparation 

of, 138 
uses of, 16 
tetra-acetate, 200-203 
tetra-butyrate, 203 
tetranitrate, 194 
threads, 229-245 

advantages of, 229 
drying of. 235 
transformation of, 7 
treatment of, with caustic alkalies, 

14, 15 
trinitrate, 195 

-vessels, change of, into wood- 
vessels, 1 
vulcanized, 90-92 
washing of, 235 
the, 70, 71 
white pieces not converted into 

fibre in, 72 
yellowish or brownish color of. 72 
yield of, 59 
Centrifugal apparatus for nitration, 

181, 182 
Chamber acid, 84 
Chardonnet artificial silk, 209-228 
M. de., apparatus for the prepa- 
ration of artificial silk by, 
217-219 
original patent of, 209, 210 
results of comparative ex- 
periments by, 212, 213 
suggestion of artificial silk 
by, 207 
Chemical wood-pulp, preparation of, 
50-81 



336 



INDEX. 



Chemicals and wood, consumption of, 

59 
Chloride of lime, bleaching with, 77 
Chlorine, disintegration of wood by, 

106 
Chromium glue, preparation of, 89, 90 
Cinnabar, coloring celluloid with, 299 
Citric acid, action of, upon cellulose, 13 
Classen' s process for the production of 

alcohol from wood, 102-107 
Cliches from celluloid, 295, 296 
Cloth-printing, viscose in, 142, 143 
Coal-tar pitch, 309, 310 
Cog wheels from viscoid, 160 
Collars and cufi's from celluloid, 297, 

298 
Collector for threads, 234 
Collodion, 193 

cotton, 166, 177 
acids for, 190 
actual, 169 
and camphor, apparatus for 

dissolving, 273 
drying of, 272, 273 
dry, solution of, 271 
for the manufacture of textile 

threads, 190 
from tissue paper, 192 
mixture of camphor with, 267 
neutralization of, 196 
nitration for the production 

of, 191 
or soluble gun-cotton, 190- 

192 
preparation of, 265, 266 
solubility of, 192, 196 
solution of, 196 
sources of, 271, 272 
test for the solubility of, 265 
testing the solubility of, 272 
uniformity of, 191 
for photographic purposes, 193- 

196 
mixture of coloring matter with, 

221, 222 
silk, 206 

solution, filtering of, 214 
preparation of, 213-215 
storage of, 196 
solvent for, 214 
spinning the, 215-217 
Coloring celluloid. 284-287 

filled celluloid masses, 291 
Combs, celluloid, manufacture of, 295 
Copper-plate engravings, celluloid 
lacquer for, 302 
plates for drying gun-cotton, 186 
recovery of, 240, 241 
Corals, imitations of, 295 



Cotton, 3-6 

apparatus for dissolving, 231, 232 
chemical composition of, 6 
destruction of structure of, 171 
determination of value of, 5 
dissolving the, in cuprammonium, 

231-233 
fabrics, transparent plates of vis- 
cose from, 136, 137 
fibre, behavior of, towards caustic 
alkalies, 14 
diameter of, 5 
length of, 5 
microscopical appearance of, 

filtering solution of, 233 
hollander for dissolving, 231, 232 
judging progress of solution of, 232 
nitrated, phvsical behavior of, 
212, 213 
results of examination of, 

212, 213 
washing of, 213 
nitration of, 178-183, 210, 213 
plant, 18 

fruit of, 4 
preparation of chemically-pure 

cellulose from, 6 
purification of, 174, 175, 230, 231 
solution, spinning the, 234-236 
Cross, preparation of viscose according 

to, 134, 135 
Crushing process, preparation of me- 
chanical wood-pulp by the, 45-47 
Cuffs and collars from celluloid, 297, 

298 
Cuprammonium, 229 

apparatus for converting cupric 

hydroxide into, 238, 239 
dissolving cotton in, 231-233 
preparation of, 237-240 
Cupric sulphate, 237 

solution, filtering of, 237 
Cuprous salts for denitration, 226 
Cylinder sieves, 36, 37 

DEHYDEATION of pulp, 40, 41 
Denitrating fluid, additions to 
the, 225 
composition of, 
220, 221 
Denitration of artificial silk, 220, 221, 

225-228 
Dentists, celluloid for the use of, 298, 

299 
Dextrin from cellulose, 12 
Dextrose, maximum yield of, 104, 105 
temperature for the formation of, 
105 



INDEX. 



337 



Dinitro-cellulose, 195 

Disintegrators, 122 

Distillation, 101 

Disulphur dichloride, preparation of, 
328-331 
quantities of, re- 
quired for the 
conversion of oils 
into factis, 326 

Doll heads of viscoid, 159 

Door handles, 159 

Dressing, use of viscose as a, 143-145 

Drying apparatus for pulp, 41, 42 
chamber for celluloid, 279, 280 
room, heating the, 186, 187 

Du Vivier, 207 

Du Vivier 's artificial silk, 222-224 

Dye-baths for artificial silk, 255 

EBONITE, 310 
Eder's investigations, 170 
Elastic masses from nitro-cellulose, 
197-200 
rubber masses, 311, 312 
Electric current, preparation of cellu- 
lose with the assistance of the, 
73-75 
process, 51 
Encrusting substance, 3 

solution and destruc- 
tion of, 20 
Esparto, use of, 77, 78 
Esters, cellulose, 200-204 

formation of, from cellulose, 14 
Ether, apparatus for the recovery of, 
275-278 
boiling point of, 274 
recovery of, 274-278 
Explosive gun-cotton, 187, 188 

FABRICS for the imitation of 
leather, 146 
viscose for marking, 143 
Factis masses, 322, 323 

preparation of, on a large scale, 

326-328 
quantities of disulphur dichloride 
required for the conversion of 
oils into, 326 
white, 325-328 
Felt, impregnation of, with viscose, 
151, 152 
nature of, 151 
Fermentation, yeast for, 100, 101 
Fibre, vulcanized, 90-92 
Fibres, plants producing. 6 
Fibroin, 205, 206, 224 
Filling materials, celluloid with, 289- 
293 

22 



Films, preparation of, 153 
Filter for collodion solution, 214 
for cotton solution, 233 

viscose solution, 248, 249 
-presses, 41 
Filtering material, 233 

water, 34 
Fir, yield of cellulose from, 59 
Flax, 6, 18 
Flock paper, 141 

Flowers, artificial, celluloid lacquer 
for, 305 
artificial, viscose in the manu- 
facture of, 152, 153 
Frames for drying gun-cotton, 186, 

187 
Frank's process for the neutralization 

of lye, 80 
Freitag's grinding machine, 31, 32 
Fremery, M., and Urban, J,, artificial 
silk according to, 242-244 

GELATINE silk, 206, 253, 254 
Glacial acetic acid, use of, for 
dissolving nitro-cellulose, 223 
Glue silk, 206 
Goldsmith, J. R. , camphor-substitute 

proposed by, 307, 308 
Gold sulphur, 309 
Gray on celluloid, 286 
Grinding machines for wood, 27-34 

wood, water used for, 34 
Grindstone for grinding wood, 27 
Gums, impression of, 299 
Gun-cotton, 161-204 

boiling or steaming of, 184 
changes in, 184 
comminution of, 184 
compression of, 187, 188 
drying the, 186, 187 
explosive, 187, 188 

acid mixture for, 177 
for blasting purposes, 187 
ignition of, 183 
modern views regarding the 

composition of, 162 
perfectly dry, storing of, 187 
preparation of. 174. 175 
soluble, acid mixture for, 177 
or collodion-cotton, 190- 
192 
solvents for, 191, 192 
storing of, 185, 186 
testing of, 185 
washing the, 183-186 
Gutta-percha printing blocks, 289 
Guttmann's plan of drying gun-cotton, 
186 



338 



INDEX. 



HAIR or wool, vegetable, 3 
Hemlock spruce, yield of cellu- 
lose from, 59 
Hemp, 6, 18 

Henckel-Donnersraark's process of 
preparing cellulose acetic-ester, 200, 
201 
Henriques, H. , investigations of, 325, 

326 
Hollander, 122 

for dissolving cotton, 231, 232 
preparation of viscose solu- 
tion, 248 
reduction of gun-cotton in the, 
184, 185 
Honig's process for the utilization of 

lye, 81 
Horse-hair, artificial, 244, 245 
Houses, portable, pasteboard for, 151 
Hummel' s process of making artificial 

silk, 207, 208 
Humus substances, 115 
Hyatt, invention of celluloid by, 263 
preparation of celluloid according 
to, 266-268 
Hydraulic press, protection of the, 213 
Hydrocarbons, heavy, use of, in the 

production of oxalic acid, 112 
Hydro-cellulose, 9-11 

composition of, 9 
manufacture of, on a large 

scale, 9-11 
preparation of an acetvl de- 
rivative from, 202/203 
properties of, 10 
sulphuretted, as rubber sub- 
stitute, 328, 329 
Hydrochloric acid, action of, upon 
cellulose, 13 
boiling wood with, 

98, 99 
disintegration of 
wood by, 51, 52 
Hydrochlorides, disintegration of wood 
by, 106 

TNCRUSTATIONS, 300 

-L Indigo-blue on celluloid, 286 

Iron in cellulose, 78 

recovery of copper by means of, 
240, 241 

vessels, celluloid lacquer for, 306 
Ivory, imitation of, 291, 292 

JAWS, impression of human, 299 
Jute, 6 
bagging, use of, 78 



K BEGAN' S process, 56, 57 
Keller, F. G., 22 
Kellner's process of preparing cellu- 
lose with the assistance of the 
electric current, 73-75 
Kneading and mixing paddle, 158 

machine, 157, 158 
Knots, machine for removal of, 25, 26 
Kristaline, 303 

LACQUER, celluloid, 302-306 
durable and resisting, 314 
Lactic acid, 126 
Langhaus's process for the preparation 

of artificial silk, 208, 209 
Lapis lazuli, imitation of, 301 
Lead acetate, treatment of nitro-cellu- 

lose with, 189 
Leather, artificial, coloring of, 147 
fabrics for, 146 
main point in the pre- 
paration of, 145 
preparation of, 145-152 
viscose solutions for, 146, 
H7 
hangings, imitations of, 141, 142 
nature of, 145 
Lederer, Ij. , preparation of an acetyl 
derivative of cellulose according to, 
202 203 
Lehner's artificial silk, 224, 225 
Liber, 3 

Liebrecht's grinding machine, 33, 34 
Lignin, solution and destruction of, 20 
Limestone, solid tufaceous, 62 
Linseed oil, 316 

final oxidation of, 318 
heating of, 317 
oxidation of, 316 
testing of. 317 
Long-staple cotton, 5 
Luck, A., and Gross, C. F. , process 
for increasing the stability of nitro- 
cellulose of, 189 
Lunge, G., and Bebie, J., investiga- 
tions of, 167 
Weintraub, E., investi- 
gations of, 163 
Lustra-cellulose and cellulose artificial 
silk, 229-245 
threads from, 246-262 
Lye and wood, proportion between, 68 
apparatus for the preparation of, 

61-66 
boiling the wood with, 67-70 
neutralization of, 80, 81 
organic substance in, 80 
pollution of streams by, 80 
preparation of, 61-66 



INDEX. 



339 



Lye, reservoirs for, 65, 60 

utilization of, in tanning, 80, 81 
Lyes, exhausted, utilization of, and 
their neutralization, 78-81 

mixed, preparation of, 113 

MAGNESIUM viscose, 133 
use of, for sizing 
paper, 139, 140 
Magnus, preparation of celluloid ac- 
cording to, 270, 271 
Manila hemp, 6 

Maps, celluloid lacquer for, 302 
Marble, imitation of, 290 

variegated, imitation of, 301 
Marine glue, 313, 314 
Mechanical wood-pulp, definition of, 
22 
or wood-stuff, 22- 

49 
preparation of, by 
the crushing 
process, 45-47 
Melting apparatus for oxalic acid; 113, 

114 
Metallic salts, behavior of viscose 
towards, 133, 134 
treatment of nitro-cellu- 
lose with, 189 
Mercer, John, discovery of, 14 
Mercerization, 14 

Metals, celluloid lacquer for, 303, 305, 
306 
for incrustations, 300 
Methyl alcohol, use of, for dissolving 

nitro-cellulose, 224 
Milk-white, definition of, 290 
Millar, A. , 207 

Millar's artificial silk, 253, 254 
Mitscherlich's process, 59-73 
Mixing machine, 157, 158 
Montejus, 231 
Mosaics, celluloid, 301, 302 
Mother-lye, 115 
Mould, plaster of Paris, 296 
Moulding hollow articles of viscoid, 

159 
Moulds for viscoid, 159 

NAPHl'HALINE, substitution of, 
for camphor, 306, 307 
Nettle, 6 

New Zealand flax, 6 
Nitrated cotton, physical behavior of, 
212, 213 
results of examination of, 

212, 213 
washing of, 213 
Nitrating apparatus, 179, 180 



Nitrating fluid, 164, 210, 211 

condition of the, 177, 178 
nature of, 176, 177 
fluids, composition of, 172, 173 

regeneration of, 177 
vessels, 177, 211 
Nitration, acid for, 175-177 

centrifugal apparatus for, 181, 182 

degrees of, 167 

effect of higher temperatures upon, 

170 
execution of, 178-183 
for the production of collodion- 
cotton, 191 
highest degrees of, 165 
influence of the content of water 

in the acid mixture upon, 168 
of cotton, 210-213 
process of, 164, 165 
stone-ware vessels for, 176 
time required for, 181 
with dry saltpetre and sulphuric 
acid, 223 
Nitric acid, action of, upon cellulose, 
13 
combinations formed by the 
action of, upon cellulose, 
161 
for collodion-cotton, 190 
the manufacture of very 
explosive products, 175 
oxidation of linseed oil with, 

318 
storage of, 176 
use of, for the disintegration 
of the wood-fibre, 51 
and sulphuric acids, mixtures of, 
for the preparation of nitro- 
cellulose, 163 
Nitro-cellulose, 161-204 

action of, towards polarized 

light, 165, 166 
and cellulose silks, difference 

between, 261 
calculation of nitrogen con- 
tained in, 166, 167 
changes in, 188. 189 
content of nitrogen in, 164 
elastic masses from, 197-200 
formation of, 162, 163 
increasing the stability of, 

188-190 
masses, inflammability of, 199 
powders for mixing with, 
199 
mixtures of sulphuric and 
nitric acids for the prepa- 
ration of, 163 
preparation of, 163 



340 



INDEX. 



Nitro-cellulose, reaction of, 192 

solution of, in volatile sol- 
vents, 197 
solvents for. 197, 223, 304 
spontaneous ignition of, 227, 
228 
-celluloses, 16, 17 
analyses of, 174 
composition of, 194 
solubility of, 169, 170 
compounds, formation and com- 
position of, 161, 162 
-oxycelluloses, 173 
Nitrogen, calculation of, contained in 

nitro-cellulose, 166, 167 
Nuts from viscoid, 160 

OBJECTS of art from celluloid, 300 
Observatories, paste-board for, 
151 
Octo-nitro-cellulose, 169 
Oil, oxidation of, 320, 321 
-rubber, 316-322 

additions to, 324 
manufacture of, on a large 
scale by means of thick oil, 
319-322 
old, restoration of, 319 
uses of, 319 
„Lick, manufacture of oil-rubber 
by means of, 319-322 
working of, 321, 322 
vulcanized, 324, 325 
Oils, drying, 316 
non-drying, 316 

quantities of disulphur dichloride 
required for the conversion of, 
into factis, 326 
sulphured, 323, 324 
Oser's grinding machine, 30 
Oxalic acid from wood cellulose, 
preparation of, 108-118 
formation of. 109 
melting apparatus for, 113, 

114 
occurrence of, 108 
preparation of, on a large 

scale. 113 
proportion between caustic 
soda and caustic potash in 
the production of, 111 
pure, from sodium oxalate, 
116 
production of, 117, 118 
use of heavy hydrocarbons in 

the production of, 112 
working up the melt, 115-117 
yields of, from sawdust, 110, 
111 



Oxygen, oxidizing action of, 316 

PANS, evaporating, 117 
Paper, cellulose in the manu- 
facture of, 16 
changes in, by parchmentiz- 

ing, 87, 88 
mills, viscose for use in, 133 
nature of, 18, 50 
sizingof, with viscose, 139, 140 
suitable for parchmentizing, 

83,84 
to be parchmentized, nature 

of, 83, 84 
use of viscose in the manu- 
facture of, 139-141 
Parchment of special thickness, pre- 
paration of, 83, 84, 88 
paper, behavior of, towards ad- 
hesive agents, 89, 90 
coloring of, 89 
flexible, 88-90 
manufacture of, on a large 

scale, 85-87 
properties of, 87, 88 
removal of acid from, 86 
vegetable, 16, 82, 92 
uses of, 90 
Parchmentizing apparatus, 85-87 
changes in paper by, 87, 88 
efiect of sulphuric acid, 82, 83 
sulphuric acid used for, 84, 85 
temperature for, 84 
Pasteboard, fire-proof, for roofing, 16 
fire-proofing of, 151 
for portable houses, 151 
impregnation of, with viscose, 150, 
151 
Pauly, Dr. Hermann, 208, 230 

artificial silk of, 230- 
236 
Peit, A., process for the manufacture 

of artificial silk, patented by, 227 
Photography, viscose in, 153, 154 
Pictures, transferring of, to celluloid 

articles, 287-289 
Pine, steaming of. 44 

yield of cellulose from, 59 
Plants, structure of. 1 
Plastite masses. 310, 311 
Polariscope, results of examination of 

nitrated cotton with the, 212, 213 
Polarized light, action of nitro-cellu- 
lose towards. 165. 166 
Poplar, yield of cellulose from, 59 
Potash, caustic, behavior of cellulose 

towards, 14 
Potassium carbonate, conversion of, 
into caustic potash, 115 



INDEX. 



341 



Potassium carbonate, recovery of, 115 
Printing blocks, gutta-percha, 289 

on celluloid, 287-289 
Pulp, 185 

bleaching agents for, 43 

change in color of, 42 

color of, 42 

dehydration of, 40, 41 

drying apparatus for, 41, 42 

effect of water on, 34 

from steamed wood, 43 

bleaching of, 48 

preparation of, by the crushing 
process, 45-47 

properties of, 42, 43 

separation of, from water, 39 

straw, bleaching of, 77 

thoroughly dried, preparation of, 
40, 41 
Pyroxylin, 161-204 

RAPE oil, 324 
Easch-Kirchner's machine for 
the preparation of pulp by the 
crushing process, 45-47 
Reagents, chemical, behavior of nat- 
ural and artificial silks towards, 
259-262 
Eed on celluloid, 285, 286 
Eefiner, 37, 38 

Eesins, addition of, to rubber, 309 
Eib-heaters, 252 

Eichter' s investigations regarding the 
denitration of artificial silk, 225, 226 
Eoofing boards, 47. 48 

fire-proof paste-board for, 16 
Eubber, additions to, 399 
artificial, 197-200 
compounds, 309-314 
filling substances for, 309 
increasing demand for, 315 
-leather, 312, 313 
masses, elastic, 311, 312 
substitute, sulphuretted hydro- 
cellulose as, 328, 329 
substitutes, 315-331 
actual, 316 
groups of, 315 
Euby shellac, 309 

SAUSAGE casings, 90 
Sawdust, action of a mixture of 
caustic soda and caustic 
potash upon, 109, 110 
fermentable sugar from, 94, 

95 
yields of oxalic acid from, 
110, 111 
Scarlet on celluloid, 285, 286 



Schulz's process for rendering nitro- 
cellulose stable, 189, 190 
Screws from viscoid, 160 
Seidel, preparation of viscose accord- 
ing to, 135-138 
Sericin, 205, 206 
Shaking sieves, Voith's, 35, 36 
Shellac, 309 
Short-staple cotton, 5 
Shuttles from viscoid, 160 
Sieves, cylinder, 36, 37 

Voith's shaking, 35, 36 
Silk, artificial, 17, 205-228 

according to M. Fremery and 

J. Urban, 242-244 
apparatus for spinning, 217- 

219 
behavior of, in a chemical 

respect, 259-262 
bleaching of, 221 
Bronnert's, 236, 237 
cellulose, 229-245 
Chardonnet, 209-222 
denitration of, 220, 221, 225- 

228 
dye baths for, 255 
Lehner's. 224, 225 
Millar's, 253, 254 
optical examination of, ^56 
Pauly's. 230-236 
Pelt's, 227 
tenacity of, 256, 257 
varieties of, 206-209 
colored artificial, preparation of, 

221, 222 
industry, artificial, historical de- 
velopment of, 207-209 
microscopical appearance of, 206 
raw, color of, 205 

composition of, 205 
scouring or boiling of, 205, 
206 
sources of, 205 

table showing diameters of various 
kinds, 256 
Silks, cellulose and nitro-cellulose, 
difference between, 261 
natural and artificial, behavior of, 
towards chemi- 
cal reagents, 
259-262 
difference between, 
255 
Silver gray on celluloid, 286 
Sinclair's boiler, 54, 55 
Size, use of viscose as a, 143-145 
Sizing, use of viscose for, 16 
Soda, caustic, and cellulose, quantita- 
tive pi-oportions of, 122 



342 



INDEX. 



Soda, caustic, behavior of cellulose 
towards, 14 
disintegration of wood by, 56, 
57 
-cellulose, 121 

commencement of formation 

of, 122, 123 
constancy of, 125 
heating of, by storing, 124 
injurious changes in, 125 
preparation of, 123, 124 
products formed by the de- 
composition of, 126 
storing of, 124-126 
temperature for storing, 125, 

126 
vessels for storing, 125 
lye and carbon disulphide, pro- 
portion between, 127 
boiling wood with, 53 
disintegration of the encrust- 
ing substance by, 52, 53 
preparation of cellulose, by means 

of, 52-59 
process, 51 

wood suitable for the, 52 
recovery of, 53, 79 
viscose, addition of bodies to, 133 
Sodium oxalate, 115 

pure oxalic acid from, 116 
sulphite, preparation of cellulose 
by means of, 58, 59 
use of, as a substitute for 
caustic soda, 53 
Soles, fabrics for, 150 
Solid spirit, 203, 204 
Soluble gun-cotton , or collodion-cotton , 

190-192 
Sorters, 35 

Sorting ground wood, 35-40 
Spinners, construction of, 234 
manufacture of, 216, 217 
Spinning apparatus, 217-219 

for viscose solution, 249, 
250 
cotton solution, 234-236 
room, removal of vapors from the, 
216, 217 
Spirit, solid, 203, 204 
Splitting machine, 26 
Spools from viscoid, 160 
Stains, process for the preparation of 
celluloid employed by the factorv 
at, 265 
Stamping mill, 71 
Starch, oxalic acid from, 108 
Steamed wood, microscopical exami- 
nation of, 45 
pulp from, 43-45 



Steaming wood, apparatus for, 44 
Stearn, preparation of textile threads 

according to, 252. 253 
Steel engravings, celluloid lacquer for, 

302 
Steenstrup's method of preparing 

rubber substitutes, 315. 316 
Sthamer, preparation of sulphuretted 

hydro-cellulose according to, 328 
Sthamer' s process of manufacturing 

hydro-cellulose, 10, 11 
Stone-ware vessels for nitration, 176 
Straw, boiling of, with lye, 76. 77 
cellulose from, 18, 19, 75-78 
preparation of, 75, 76 

of cellulose from, 2, 3 
pulp, bleaching of, 77 
winnowed, working of, 76 
yield of cellulose from, 77 
Sugar and alcohol, production of, 
from wood-cellulose, 93-107 
fermentable, conversion of cellu- 
lose into, 17 
from wood, more modem 
methods for the 
production of, 
98-102 
older methods for 
the production 
of, 94-98 
Sulphite-cellulose according to Mit- 
scherlich's process, 59- 
73 
plant, water required in 

a, 59, 60 
preparation of wood for, 

60 
viscose from, 135, 136 
process, 51 

irregularities in, 66 
operations in the, 61 
preparation of lye for, 61-66 
of sulphurous acid for, 62 
solution, preparation of, 61-66 
Sulphites, preparation of cellulose 

with the assistance of, 59-73 
Sulphur burning, 62 

causes of incomplete combustion 

of, 62 
unburnt, test for, 62, 63 
Sulphured oils, 323, 324 
Sulphuretted hydro-cellulose as rubber 
substitute, 328, 329 
hydrogen, evolution of, from vis- 
cose solution, 130, 131 
Sulphuric acid, behavior of celluloid 
towards, 282 
concentrated, effect of, 
on thread, 243, 244 



INDEX. 



343 



Sulphuric acid, effect of, upon cellulose, 
12, 13, 82 
upon wood, 103 
for collodion-cotton, 190 

nitration, 176 
parchmentizing effect of, 

82, 83 
production of, 105 
recovery of, 86, 87 
storage of, 176 
used for parchmentizing, 
84,85 
and nitric acids, mixtures of, for 
the preparation of nitro-cellu- 
lose, 163 
anhydride, treatment of wood by, 
106 
Sulphurous acid, action of, upon cel- 
lulose, 13 
bleaching pulp with, 43 
preparation of, 62 
recovery of, 70 

TABLE showing changes in paper 
by parchmentizing, 88 
comparative tenacity of 

artificial silk, 257 
diameters of various 

kinds of silk, 256 
effect of higher tempera- 
tures upon nitration, 
170 
influence of content of 
water in the acid mixt- 
ure upon nitration, 
168 
proportion between 
caustic sodaand caustic 
potash in the produc- 
tion of oxalic acid, 
110, 111 
quantities of disulphur 
dichloride required 
for the conversion of 
oils into factis, 326 
Tanning, utilization of lye in, 80. 81 
Tar colors, printing with, on celluloid, 

289 
Tartaric acid, action of, upon cellu- 
lose, 13 
Textile threads, collodion-cotton for, 
190 
from purecellulose, 208,209 
viscose. 246-262 

according to Stearn, 
252, 253 
produced by artificial 
means, general proper- 
ties of, 254-262 



Thorn's investigations regarding the 

production of oxalic acid, 109-112 
Thread, drying process for, 242, 243 
effect of concentrated sulphuric 
acid on, 243, 244 
Threads, cellulose, 229-245 
collector for, 234 
effect of water on, 254 
from lustra-cellulose, 246-262 
microscopical examination of, 

255, 2-56 
reeling up of, 235 
textile, from viscose. 246-262 

produced by artificial means, 
general properties of, 254- 
262 
uniform, of larger diameter, 245 
Tissue, loosely woven, treatment of, 
137 
mode of sizing a, with viscose, 144 
Torpedoes, gun-cotton for loading, 188 
Tortoise-shell, imitation of, 292 
Tower, absorbing, for the preparation 

of lye. 63-66 
Tribouillet and Besancele, preparation 

of celluloid according to, 268, 269 
Tubes, celluloid, 294 



u 



NGERER'S boiling process, 55 



VARNISH, resisting, preparation of, 
325 
Vegetable parchment, 16, 82-92 
Velvet hangings, imitations of, 141, 142 
Ventilating hood, 178, 179 
Victoria lacquer, 303 
Violet on celluloid, 286 
Viscoid and viscose, 119-160 

articles, painting of, 159, 160 
conversion of viscose into, 132, 133 
masses, 154-160 

preparation of larger quanti- 
ties of, 157-160 
properties of, 157 
white, 155, 156 
moulding hollow articles of, 159 
plates and blocks from, 132, 133 
cause of dull specks in, 133 
uses of, 160 
Viscose and viscoid, 119-160 
apparatus for preparing, 127 
as a size or dressing, 143-145 
behavior of. towards metallic 

salts, 133, 134 
cellulose for the preparation of, 

121, 122 
chemically pure, preparation of, 
138 



544 



INDEX. 



Viscose, coloring of, 247 

conversion of, into viscoid, 119, 

120, 132, 133, 250 
cost of producing threads from, 

246 
experiments with, 246 
films of, 133 
for marking fabrics, 143 
impregnation of felt with, 161, 
162 
paste board with, 
150, 151 
in cloth printing, 142, 143 
photography, 153, 154 
the manufacture of artificial 
flowers, 152, 153 
of wall paper. 141, 142 
incorporation of foreign bodies 

with, 155, 156 
modifications in the process of 

preparing, 120 
preparation of, 126-128 

according to Cross, 
134, 135 
to Seidel, 135- 
138 
films from, 153, 154 
leather-like bodies 
by means of, 145- 
152 
on a large scale, 
121-124 
small scale, 120, 
121 
pure cellulose from, 246 
replacing the soda in, by am- 
monia, 131 
shipping of, 130 
solution, changes in, 130 

decomposition of, 130, 131 
filtering of, 248, 249 
for the preparation of silk- 
threads, 209 
preparation of, 128, 129, 248 
spinning apparatus for, 249, 
250 
solutions for the preparation of 
artificial leather, 146, 147 
properties of, 130-132 
stability of, 129 
storing of, 129, 130 
temperature for storing, 129, 130 
textile threads from, 246-262 

according t o 
Steam, 252, 
253 
threads, 132 

quality of, 247 
treatment of, 250, 251 



Viscose, use of, in the manufacture of 
paper, 139-141 
uses of, 16, 138, 139 
vessels for shipping, 130 
storing, 129 
Voelter, Heinrich, 22 

grinding machine of, 

28-30 
process of wood grinding 
of, 23 
Voith's shaking sieves, 35, 36 

wood-grinding machine, 31 
Vulcanized cellulose, 90-92 
fibre, 90-92 
oil, 324, 325 

WALL paper, viscose in the manu- 
facture of. 141, 142 
Wash room, 183 

tank, 183 
Washing machines, 57 
Waste water, discharge of, 59, 60 
Water, behavior of celluloid towards, 
8, 9, 282 
effect of, on pulp, 34 
filtering of, 34 
separation of pulp from, 39 
used for grinding. 34 
Weapons, celluloid lacquer for, 303 
White factis, 325-328 
Winkler, CI., experiments of, 42 
Wood, alcohol from, 12 

Classen's process, 
102-107 
value of, 102 
and chemicals, consumption of, 59 

lye, proportion between, 68 
apparatus for steaming. 44 

the production of 
alcohol from, 97 
battery for lixiviation of, 57 
boiling of, under pressure, 98, 99 
with lye, 67-70 
soda lye, 53 
cellulose from, 3 

preparation of, 50-81 

of oxalic acid from, 
108-118 
production of sugar and alco- 
hol from, 93-107 
dead-ground, 33 

disintegration of, by chlorine, 106 
hydrochloric 
acid, 51 ,52 
hypo chlor- 
ides, 106 
encrusting substance of. 3 
extractive substances in, 108 
-fibre, disintegration of, by acid8,51 



INDEX. 



545 



Wood for grinding, 23, 24 
grinding machines, 27-34 

process, first patent for, 22 
Voelter's, 23 
grindstone for grinding, 27 
ground, physical properties of, 
48, 49 
sorting of, 35-40 
hydraulic pressure in grinding, 

33,34 
machine for removing knots from, 
25, 26 
for removing the bark from, 
24, 25 
mill for the further reduction of, 

37, 38 
more modern methods for the pro- 
duction of fermentable sugar 
from, 94-98 
nature of, to be worked for alco- 
hol, 96-98 
older methods for the production 
of fermentable sugar from, 94- 
98 
origin of the idea of grinding, 22 
preparation of cellulose from, 50- 
81 
of, for sulphite cellulose, 
60 
-pulp, chemical, preparation of, 
50-81 
mechanical, definition of, 22 
or wood-stuff, 22-49 
preparation of, by the 
crushingprocess, 45- 
47 
properties of, 42, 43 
qualities of, 19 
reduction of, 19, 94 
soaking of, 94 

spirit, use of, for dissolving nitro- 
cellulose, 224 



Wood, splitting machine for, 26 

steamed, microscopical examina- 
tion of, 45 
pulp from, 43-45 
-stuff, definition of, 22 

or mechanical wood-pulp, 
22-49 
suitable for the soda process, 52 
tar, 15 

threads from, 21 
to be ground, preparation of, 24- 

26 
treatment of, by sulphuric anhy- 
dride, 106 
varieties of, suitable for grinding 
23, 24 
for the production 
of alcohol, 97 
for sulphite-cellulose, 
60, 61 
-vessels, change of cellulose- 
vessels into, 1 
vinegar, 15 

water used for grinding, 34 
yield of alcohol from, 107 
Wool tree, 6 

Wrapping paper, sizing of, with vis- 
cose, 140 
stout, 44 

TTEAST for fermentation, 100, 101 

ZAPON, 303 
Zetterlund, process of, for the 
production of ferraentablesugar 
from wood. 94, 95 
Zinc acetate, treatment of nitro-cellu- 

lose with, 189 
Zuhl and Eisemann, camphor-substi- 
tutes proposed by, 307 



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AMATEUR MECHANICS' WORKSHOP: 

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Embracing all those w^hich are most important in Dynamics, Hy- 
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Gearing, Presses, Horology and Miscellaneous Machinery ; and in- 
cluding many movements never before published, and several of 
which have only recently come into use. By Henry T. Brown. 
i2mo $1.00 

BUCKMASTER.— The Elements of Mechanical Physics : 
By J. C. BucKMASTER. Illustrated with numerous engravings. 
l2mo i^l.oo 

BULLOCK. — The American Cottage Builder : 

A Series of Designs, Plans and Speciticallons, from ^200 to ^20,000, 
for Homes for the People ; together with Warming, Ventilation, 
Drainage, Painting and Landscape Gardening. By John Bullock, 
Architect and Editor of "The Rudiments of Architecture and 
Building," etc., etc. Illustrated by 75 engravings. 8vo. ^2.50 

BULLOCK. — The Rudiments of Architecture and Building : 
For the use of Architects, Builders, Draughtsmen, Machinists, En- 
gineers and Mechanics. Edited by John Bullock, author of " The 
American Cottage Builder." Illustrated by 250 Engravings. Svo. $2.50 

BURGH. — Practical Rules for the Proportions of Modem 
Engines and Boilers for Land and Marine Purposes. 
By N. P. Burgh, Engineer. i2mo. .... $1.50 

BYLES. — Sophisms of Free Trade and Popular Political 

Economy Examined. 

By a Barrister (Sir John Barnard Byles, Judge of Common 

Pleas). From the Ninth English Edition, as published by the 

Manchester Reciprocity Association. i2mo. . . . $1.25 

BOWMAN.— The Structure of the Wool Fibre in its Relation 
to the Use of Wool for Technical Purposes : 
Being the substance, with additions, of Five Lectures, deliverea at 
the request of the Council, to the members of the Bradford Technical 
College, and the Society of Dyers and Colorists. By F. FI. Bow- 
man, D. Sc, F. R. S. E., F. L. S. Illustrated by 32 engravings. 
8vo fc.oo, 

BYRNE. — Hand-Book for the Artisan, Mechanic, and Eneri- 

neer : 

Comprising the Grinding and Shnrpening of Cutting Tools, Abvas.ve 

Processes, Lapidary Work, Gem and Glass Engraving, Varnishing 

and Lackering, Apparatus, Materials and Processes for Grinding and 



HENRY CAREY BAIRD & CO.'S CATALOGUE. 



Polishing, etc. By Oliver Byrne. Illustrated by 185 wood en- 
gravings. 8vo. ........ $!)-Oi. 

BYRNE. — Pocket-Book for Railroad and Civil Engineers : 

Containing New, Exact and Concise Methods for Laying out Railroad 
Curves, Switches, Frog Angles and Crossings; the Staking out of 
work; Levelling; the Calculation of Cuttings; Embankments; Earth- 
work, etc. By Oliver Byrne. i8mo., full bound, pocket-book 

form r . . ^1.50 

BYRNE. — The Practical Metal- Worker's Assistant: 
Comprising Metallurgic Chemistry; the Arts of Working all Metals 
and Alloys ; Forging of Iron and Steel ; Hardening and Tempering; 
Melting and Mixing; Casting and Founding; Works in Sheet Metal; 
the Processes Dependent on the Ductility of the Metals; Soldering; 
and the most Improved Processes and Tools employed by Metal- 
workers. With the Application of the Art of Electro-Metallurgy to 
Manufacturing Processes ; collected from Original Sources, and from 
the works of Holtzapfifel, Bergeron, Leupold, Piumier, Napier, 
Scoffern, Clay, Fairbairn and others. By Oliver Byrne. A new, 
revised and improved edition, to which is added an Appendix, con- 
taining The Manufacture of Russian Sheet- Iron. By John Percy, 
M. D., F. R. S. The Manufacture of Malleable Iron Castings, and 
Improvements in Bessemer Steel. By A. A. Fesquet, Chemist and 
Engineer. With over Six Hundred Engravings, Illustrating every 

Branch of the Subject. 8vo 1^5.00 

BYRNE.— The Practical Model Calculator: 

For the Engineer, Mechanic, Manufacturer of Engine Work, Naval 
Architect, Miner and Millwright. By Oliver Byrne. 8 vo., nearly 

600 pages $3-°'^ 

CABINET MAKER'S ALBUM OF FURNITURE; 
Comprising a Collection of Designs for various Styles of Furniture. 
Illustrated by Forty-eight Large and Beautifully Engra\-"=;d Plates. 

Oblong, 8vo *i-50 

CALLINGHAM.— Sign Writing and Glass Embossing: 

A Complete Practical Illustrated Manual of the Art. By James 
CALLINGHAM. To which are added Numerous Alphabets and the 
Art of Letter Painting Made Easy. By James C. Badenoch. 258 

pages. i2mo. fi-S^ 

CAMPIN. — A Practical Treatise on Mechanical Engineering: 
Comprising Metallurgy, Moulding, Casting, Forging', Tools, Workc 
shop Machinery, Mechanical Manipulation, Manufacture of Steam- 
Engines, etc. With an Appendix on the Analysis of Iron and Iron 
Ores. By Fpancis Campin, C. E. To which are added, Observations 
on the Construction of Steam Boilers, and Remarks upon Furnaces 
used for Smoke Prevention ; with a Chapter on Explosions. By R. 
Armstrong, C. E., and John Bourne. (Scarce.) 



HENRY CAREY BAIRD & CO.*S CATALOGUE. 



CAREY.— A Memoir of Henry C. Carey. 

By Dr. Wm. Elder. With a portrait. 8vo., cloth . . 75 

CAREY.— The Works of Henry C. Carey : 

Harmony of Interests : Agricultural, Manufacturing and Commer- 
cial. 8vo. ..... . . $1.25 

Manual of Social Science. Condensed from Carey's " Principles 
of Social Science." By Kate McKean. i vol. i2mo. . $2.oa 
Miscellaneous Works. With a Portrait. 2 vols. 8vo. ^io.oo_ 

Past, Present and Future. 8vo ^2.50j 

Principles of Social Science. 3 volumes, 8vo. . . $7.50' 
The Slave-Trade, Domestic and Foreign; Why it Exists, and 
How it may be Extinguished (1853). 8vo. , . . ^2.00 
The Unity of Law : As Exhibited in the Relations of Physical, 
Social, Mental and Moral Science (1872). 8vo. . . ^2.50 

CLARK. — Tramways, their Construction and Working : 

Embracing a Comprehensive History of the System. With an ex' 
haustive analysis of the various modes of traction, including horse- 
power, steam, heated water a.id compressed air; a description of the 
varieties of Rolling stock, and ample details of cost and working ex- 
penses. By D. KiNNEAR Clark. Illustrated by over 200 wood 
engravings, and thirteen folding plates. I vol. Svo. . ^7.50 

COLBURN.— The Locomotive Engine : 

Including a Description of its Structure, Rules for Estimating its 
Capabilities, and Practical Observations on its Construction and Man- 
agement. By Zerah CoLBURN. Illustrated. i2mo. . ;^i.oo 

COLLENS. — The Eden of Labor; or, the Christian l^topia. 
By T. Wharton Collens, author of " Humanics," "The Historj 
of Charity," etc. i2mo. Paper cover, ^i. 00; Cloth . ^1.25 

COOLEY. — A Complete Practical Treatise on Perfumery: 
Being a Hand-book of Perfumes, Cosmetics and other Toilet Article! 
With a Comprehensive Collection of Formulae. By Arnold J, 
CooLEY. i2mo. ........ ^1.50 

COOPER.— A Treatise on the use of Belting for t\e Trantr- 
mission of Power. 
With numerous illustrations of approved and actual methods of ar- 
ranging Main Driving and Quarter Twist Belts, and of Belt Fasten 
ings. Examples and Rules in great number for exhibiting and cal- 
culating the size and driving power of Belts. Plain, Particular and 
Practical DiVections for the Treatment, Care and Manigement o^ 
Belts. Descriptions of many varieties of Beltings, together witn 
chapters on the Transmission of Power by Ropes ; by Iron and 
Wood Frictional Gearing; on the Strength of Belting Leather; and 
on the Experimental Investigations of Morin, Briggs, and others. Bf 
John H. Cooper, M. E. Svo $3-50 

CRAIK. — The Practical American Millwright and MiWer. 

By David Craik, Millwright. Illustrated by aumerous wood en- 
gravings and two folding plates. Svo (Scarce.) 



HENRY CAREY BAIRD & CO.'S CATALOGUE. 9 

CROSS. — The Cotton Yarn Spinner : 

Showing how the Preparation should be arranged for Different 
Counts of Yarns by a System more uniform than has hitherto been 
practiced; by having a Standard Schedule from which we make all 
our Changes. By Richard Cross. 122 pp. i2mo. . 75 

CRISTIANI. — A Technical Treatise on Soap and Candles: 

With a Glance at the Industry of Fats and Oils. By R. S. Cris- 
TIANI, Chemist. Author of " Perfumery and Kindred Arts." Illus- 
trated by 176 engravings. 581 pages, 8vo. ^15.00 

COURTNEY. — The Boiler Maker's Assistant in Drawing, 
Templating, and Calculating Boiler Work and Tank 
Work, etc. 
Revised liy D. K. Clark. 102 ills. Fifth edition. . . 80 
COURTNEY.— The Boiler Maker's Ready Reckoner: 

With Examples of Practical Geometry and Templating. Revised by 
D. K. Clark, C. E. 37 illustrations. Fifth edition. • |i-6o 

DAVIDSON.— A Practical Manual of House Painting, Grain- 
ing, Marbling, and Sign- Writing: 
Containing full information on the processes of House Painting in 
Oil and Distemper, the Formation of Letters and Practice of Sign- 
Writing, the Principles of Decorative Art, a Course of Elementary 
Drawing for House Painters, Writers, etc., and a Collection of Useful 
Receipts. W^ith nine colored illustrations of Woods and Marbles, 
and numerous wood engravings. By Ellis A Davidson. i2mo. 

$2.00 

DAVIES.— A Treatise on Earthy and Other Minerals and 
Mining: 
By D. C Davies, F. G. S., Mining Engineer, etc. Illustrated by 
76 Engravings. l2mo $5-^'^ 

DAVIES. — A Treatise on Metalliferous Minerals and Mining: 
By D. C. Davies, F. G. S , Mining Engineer, Examiner of Mines, 
Quarries and Collieries. Illustrated by 148 engravings of Geological 
Formations, Mining Operations and Machinery, drawn from the 
practice of all parts of the world. Fifth Edition, thoroughly Revised 
and much Enlarged by his son, E. Henry Davies. i2mo , 524 
pages • • ^5-oo 

DAVIES.— A Treatise on Slate and Slate Quarrying: 

Scientific, Practical and Commercial. By D. C. Davies, F. G. S., 
Mining Engineer, etc. Witli numerous illustrations and foldmg 
plates. 3 2mo. $1.20 

DAVIS. — A Practical Treatise on the Manufacture of Brick, 

Tiles and Terra-Cotta : 

Including Stiff Clay, Dry Clay, Hand Made, Pressed or Front, and 

Roadway Paving Brick, Enamelled Brick, with Glazes and Colors, 

Fire Brick and Blocks. Silica Brick, Carbon Brick, Glass Pots, Re- 



lo HENRY CAREY BAIRD & CO.'S CATALOGLb. 

torts, Avchitectural Tena-Cotta, Sewer Pipe, Drain Tile, Glazed and 
Unglazed Roofing Tile, Art Tile, Mosaics, and Imitation of Intarsia 
or Inlaid Surfaces. Comprising every product of Clay employed in 
Architecture, Engineering, and the Blast Furnace. With a Detailed 
Description of tiie Different Clays employed, the Most Modern 
Machinery, Tools, and Kilns used, and the Processes for Handling, 
Disintegrating, Tempering, and Moulding the Clay into Shape, Dry- 
fng, Setting, and Burning. By Charles Thomas Davis. Third Edi- 
tion. Revised and in great part rewritten. Illustrated by 261 
engravings. 662 pages ....... ^5.00 

DAVIS. — A Treatise on Steam-Boiler Incrustation and Meth- 
ods for Preventing Corrosion and the Formation of Scale: 
By Charles T. Davis. Illustrated by 65 engravings. 8vo. 

DAVIS.~The Manufacture of Paper: 

Being a Description of the various Processes for the Fabrication, 
Coloring and Finishing of every kind of Paper, Including the Dif- 
ferent Raw Materials and the Methods for Determining their Values, 
the Tools, Machines and Practical Details connected with an intelli- 
gent and a profitable prosecution of the art, with special reference to 
the best American Practice. To which are added a History of Pa- 
per, complete Lists of Paper-Making Materials, List of American 
Machines, Tools and Processes used in treating the Raw Materials, 
and in Making, Coloring and Finishing Paper. By Charles T. 
Davis. Illustrated by 156 engravings. 608 pages, 8vo. $6.00 

DAVIS. — The Manufacture of Leather: 

Being a Description of all the Processes for the Tanning and Tawing 
with Bark, Extracts, Chrome and all Modern Tannages in General 
Use, and the Currying, Finishing and Dyeing of Every Kind of Leather; 
Including the Various Raw Materials, the Tools, Machines, and all 
Details of Importance Connected with an Intelligent and Profitable 
Prosecution of the Art, with Special Reference to the Best American 
Practice. To which are added Lists of American Patents (1884— 1897) 
for Materials, Processes, Tools and Machines for Tanning, Currying, 
etc. By Charles Thomas Davis. Second Edition, Revised, and 
in great part Rewritten. Illustrated by 147 engravings and 14 Sam- 
ples of Quebracho Tanned and Aniline Dyed Leathers. 8vo, cloth, 
712 pages. Price . $7-5o 

DAWIDOWSKY— BRANNT.— A Practical Treatise on the 

Raw Materials and Fabrication of Glue, Gelatine, Gelatine 

Veneers and Foils, Isinglass, Cements, Pastes, Mucilages, 

etc. : 

Eased upon Actual Experience. By F. Dawidowsky, Technical 

Chemist. Translated from the German, with extensive additions, 

including a description of the most Recent American Processes, by 

William T. Brannt, Graduate of the Royal Agricultural College 

of Eldena, Prussia. 35 Engravings. l2mo. . . . ^^2.50 

DE GRAFF.— The Geometrical Stair-Builders* Guide : 
Being a Plain Practical System of Hand-Railing, embracing all its 
necessary Details, and Geometrically Illustrated by twenty-two Steel 
Engravings ; together with the use of the most approved pnnciple.* 
nf Practical Geometry. By Simon De Graff, Architect, (Scarce.) 



HENRY CAREY BAIRD & CO.'S CATALOGUE. ii 

DE KONINCK— DIETZ.— A Practical Manual of Chemical 
Analysis and Assaying : 
As applied to the Manufacture of Iron from its Ores, and to Cast Iron, 
Wrought Iron, and Steel, as found in Commerce. By L. L. De 
K.ONINCK, Dr. Sc, and E. Dietz, Engineer. Edited with Notes, by 
Robert Mallet, F. R. S., F. S. G., M. I. C. E., etc. Americaa 
Edition, Edited with Notes and an Appendix on Iron Ores, by A. A. 
Fesquet, Chemist and Engineer. i2mo. . . . $1.50 

DUNCAN.— Practical Surveyor's Guide: 

Containing the necessary information to make any person of com^ 
mon capacity, a finished land surveyor without the aid of a teacher 
By Andrew Duncan. Revised. 72 engravings, 214pp. l2mo. $1.50 

DUPLAIS. — A Treatise on the Manufacture and Distillation 
of Alcoholic Liquors : 
Comprising Accurate and Complete Details in Regard to Alcohol 
from Wine, Molasses, Beets, Grain, Rice, Potatoes, Sorghum, Asphc 
del. Fruits, etc. ; with the Distillation and Rectification of Brandy 
Whiskey, Rum, Gin, Swiss Absinthe, etc., the Preparation of Aro- 
matic Waters, Volatile Oils or. Essences, Sugars, Syrups, Aromatic 
.Tinctures, Liqueurs, Cordial Wines, Effervescing Wines, etc., the 
Ageing of Brandy and the improvement of Spirits, with Copious 
Directions and Tables for Testing and Reducing Sjiirituous Liquors, 
etc,o £tc. Translated and Edited from the French of MM. DUPLAIS, 
By M. McKennie, M. D. Illustrated. 743 pp. 8vo. ^15.00 

DYER AND COLOR-MAKER'S COMPANION : 

Containing upwards of two hundred Receipts for making Colors, on 
ihe most approved principles, for all the various styles and fabrics now 
in evistence ; with the Scouring Process, and plain Directions for 
Preparing, Washing-oft", and Finishing the Goods. i2mo. $1 00 

EIDHERR. — The Techno-Chemical Guide to Distillation: 
A Hand-Book for the Manufacture of Alcohol and Alcoholic Liquors, 
including the Preparation of Malt and Compressed Yeast. Edited 
from the German of Ed. Eidherr. Fully illustrated, (In preparation.) 

EDWARDS. — A Catechism of the Marine Steam-Engine, 
For the use of Engineers, Firemen, and Mechanics. A Practical 
Work for Practical Men. By Emory Edwards, Mechanical _ Engi- 
neer. Illustrated by sixty-three Engravings, including examples of 
the most modern Engines. Third edition, thoroughly revised, with 
much additional matter. l2mo. 414 pages . . . ^2 00 

EDWARDS. — Modern American Locomotive Engines, 
Their Design, Construction and Management. By Emory Edwards,( 
Illustrated l2mo ^2.00 

EDWARDS. — The American Steam Engineer: 

Theoretical and Practical, with examples of the latest and most ap- 
proved American practice in the design and construction of Steam 
Engines and Boilers. For the use of engineers, machinists, boiler- 
i«akers, and engineering students. By Emory Edwards. Fully 
illustrated, 419 pages. i2mo. • . - . S2.SO 



HENRY CAREY BAIRD & CO.'S CATALOGUE. 



EDWARDS. — Modern American Marine Engines, Boilers, 3Il4 
Screw Propellers, 

Their Design and Construction. Showing the jPresent Practice ot 
the most Eminent Engineers and Marine Engine Builders in the 
United States. Illustrated by 30 large and elaborate plates. 4to. ^5.0C 
EDWARDS.— The Practical Steam Engineer's Guide 

In the Design, Construction, and Management of American Stationary, 
Portable, and Steam Fire- Engines, Steam Pumps, Boilers, Injector^ 
Governors, Indicators, Pistons and Rings, Safety Valves and Steam 
Gauges. For the use of Engineers, Firemen, and Steam Users. By 
Emory Edwards. Illustrated by 119 engravings, a.20 pages. 
i2mo. .......... ^2 50 

EISSLER.— The Metallurgy of Gold : 

A Practical Treatise on the Metallurgical Treatment of Gold-Bear- 
ing Ores, including the Processes of Concentration and Chlorination, 
and the Assaying, Melting, and Refining of Gold. By M. Eissler. 

With 132 Illustrations. i2mo. ^7.50 

EISSLER.— The Metallurgy of Silver : 

A Practical Treatise on the Amalgamation, Roasting, and Lixiviation 
of Silver Ores, including the Assaying, Melting, and Refining of 
Silver Bullion. By M. Eissler. 124 Illustrations. 336 pp. 

i2mo $4-2$ 

ELDER. — Conversations on the Principal Subjects of Political 
Economy. 
By Dr. William Elder. 8vo ^2,50 

ELDER.— Questions of the Day, 

Economic and Social. By Dr. William Elder. 8vo. . $3.00 
ERNI AND BROWN.— Mineralogy Simplified. 

Easy Methods of Identifying Minerals, including Ores, by Means of 
the Blow-pipe, by Flame Reactions, by Humid Chemical Analysis, 
and by Physical Tests. By Henri Erni, A. M., M. D. Third Edi- 
tion, revised, re-arranged and with the addition of entirely new matter, 
including Tables for the Determination of Minerals by Chemical and 
Pyrognostic Characters, and by Physical Characters. By Amos P. 
Brown, E. M., Ph. D. 350 pp., illustrated by 96 engravings, pocket- 
bo6k form, full flexible morocco, gilt edges . . . ^2.50 
FAIRBAIRN.— The Prmciples of Mechanism and Machinery 
of Transmission * 
Comprising the Principles of Mechanism, Wheels, and PuUevs, 
Strength and Proportions of Shafts, Coupling of Shafts, and Engag- 
ing and Disengaging Gear. By SiR William Fairbairn, Bart 
C. E. Beautifully illustrated by over 150 wood-cuts. In one 

yolume. i2mo ;^2.oo 

FLEMING. — Narrow Gauge Railways in America. 
A Sketch of their Rise, Progress, and Success. Valuable Statistics 
is to Grades, Curves, Weight of Rad, Locomotives, Cars, etc. By 
Howard Fleming. Illustrated, 8vo. . . . . $1 oa 
FORSYTH.— Book of Designs for Headstones. Mural, and 
oth&r Monuments : 
Containing 78 Designs. By James Forsyth. With an Introduction 
by Charles Boutell, M. A. ^ to., cloth -•-. » • 1^3.50 



HENRY CAREY BAIRD & CO.'S CATALOGUE. 13 



FRANKEL— HUTTER.— A Practical Treatise on the Manu* 
facture of Starch, Glucose, Starch-Sugar, and Dextrine: 
Based on the German of Ladislaus Von Wagner, Professor in the 
Royal Technical High School, Buda-Pest, Hungary, and other 
authorities. By Julius Frankel, Graduate of the Polytechnic 
School of Hanover. Edited by Robert Hutter, Chemist, Practical 
Manufacturer of Starch-Sugar. Illustrated by 58 engravings, cover- 
ing every branch of the subject, including examples of the most 
Recent and Best American Machinery. 8vo., 344 pp. . $3. 50 

GARDNER.— The Painter's Encyclopaedia: 
Containing Definitions of aU Important Words in the Art of Plain 
and Artistic Painting, with Details of Practice in Coach, Carriage, 
Railway Car, House, Sign, and Ornamental Painting, including 
Graining, Marbling, Staining, Varnishing, Polishing, Lettering, 
Stenciling, Gilding, Bronzing, etc. By Franklin B. Gardner. 
158 Illustrations. i2mo. 427 pp. ..... ^2.00 

GARDNER.— Everybody's Paint Book : 

A Complete Guide to the Art of Outdoor and Indoor Painting. 38 
illustrations i2mo, 183 pp. ...... ^I.oo 

GEE. — The Jeweller's Assistant in the Art of Working in 
Gold: 
A Practical Treatise for Masters and Workmen. i2mo. . $3-00 

GEE. — The Goldsmith's Handbook : 

Containing full instructions for the Alloying and Working of Gold, 
including the Art of Alloying, Melting, Reducing, Coloring, Col- 
lecting, and Refining; the Processes of Manipulation, Recovery of 
Waste ; Chemical and Physical Properties of Gold ; with a New 
System of Mixing its Alloys ; Solders, Enamels, and other Useful 
Rules and Recipes. By George E. Gee. i2mo, ^ . ;^i.25 

GEE. — The Silversmith's Handbook : 

Containing full instructions for the Alloying and Working of Silver, 
including the different modes of Refinir-^ :ind Melting the Metal; its 
Solders; the Preparation of Imitation Alloys; Methods of Manipula- 
tion; Prevention of Waste ; Instructions for Improving and Finishing 
the Surface of the Work; together with other Useful Information and 
Memoranda. By George E. Gee. Illustrated. i2mo. Si. 25 

GOTHIC ALBUM FOR CABINET-MAKERS: 

Designs for Gothic Furniture. Twenty-three plates. Oblong ^1.50 

'iRANT. — A Handbook on the Teeth of Gears : 
Their Curves, Properties, and Practical Construction. By George 
B. Grant. Illustrated. Third Edition, enlarged. 8vo. ^i.oo 

GREENWOOD.— Steel and Iron: 

Comprising the Practice and Theory of the Several Methods Pur- 
sued in their Manufacture, and of their Treatment in the Rolling- 
Mills, the Forge, and the Foundry. By William Henry Green- 
wood, F. C. S- With 97 Diagrams, 536 pages. i2mo. ^1.75 



14 HENRY CAREY BAIRD & CO.'S CATALOGUE 



GREGORY. — Mathematics for Practical Men : 

Adapted to the Pursuits of Surveyors, Architects, Mechanics, and 
Civil Ewgineers. By Olinthus Gregory. 8vo., plates 1^3. oo, 
GRISWOLD. — Railroad Engineer's Pocket Companion for thi 
Field : 
Comprising Rules for Calculating Deflection Distances and Angles, 
Tangential Distances and Angles, and all Necessary Tables for En 
gineers; also the Art of Levelling from Preliminary Survey to th« 
Construction of Railroads, intended Expressly for the Young En- 
gineer, together with Numerous Valuable Rules and Examples. By 

W. Griswolu. i2mo., tucks $i-So 

GRUNER.— Studies of Blast Furnace Phenomena: 

By M. L. Gruner, President of the General Council of Mines o5 
France, and lately Piofessor of Metallurgy at the Ecole des Mines. 
Translated, with the author's sanction, with an Appendix, by L. D. 
B. Gordon, F. R. S. E., F. G. S. 8vo. . . , ^2.50 

Hand-Book of Useful Tables for the Lumberman, Farmer and 
Mechanic : 

Containing Accurate Tables of Logs Reduced to Inch Board Meas- 
ure, Plank, Scantling and Timber Measure ; Wages and Rent, by 
Week or Month ; Capacity of Granaries, Bins and Cisterns ; Land 
Measure, Interest Tables, with Directions for Finding the Interest on 
any sum at 4, 5, 6, 7 and 8 per cent., and many other Useful Tables. 
32 mo., boards. 186 pages .25 

HASERICK.— The Secrets of the Art of Dyeing Wool, Cotton, 
and Linen, 
Including Bleaching an-i Coloring Wool and Cotton Hosiery and 
Random Yarns. A Treatise based on Economy and Practice. By 
E. C. Haserick. Illustrated by 323 Dyed Patterns of the Yami 
or Fabrics. 8vo. ........ ^5-00 

HATS AND FELTING: 

A Practical Treatise on their Manufacture. By a Practical Hatie*-, 
Illustrated by Drawings of Machinery, etc. 8vo. . . ^1.25 

HERMANN.— Painting on Glass and Porcelain, and Enamel 
Painting: 
A Complete Introduction to the Preparation of all the Colors and 
Fluxes Used for Painting on Glass, Porcelain, Enamel, Faience and 
Stonev/are, the Color Pastes and Colored Glasses, together with a 
Minute Description ot the Firing ol Colors and Enamels, on the 
Basis of Personal Practical Experience of the Art up to Date. 18 
illustrations. Second edition. 

HAUPT. — Street Railway Motors: 

With Descriptions and Cost of Plants and Operation of the Various 
Systems now in Use. 12W0. , ... ;g 1.75 



HENRY CAREY BAIRD & CO.'S CATALOGUE. 15 

HAUPT. — A Manual of Engineering Specifications and Con- 
tracts. 

By Lewis M. Haupt, C. E. Illustrated with numerous maps. 
328pp. 8vo ■ ;^3 00 

HAUPT.— The Topographer, His Instruments and Methods. 
By Lewis M. Haupt, A. M., C. E. Illustrated with numerous 
plates, maps and engravings. 247 pp. 8vo, . . . ^3.00 

HUGHES. — American Miller and Millwright's Assistant: 
By William Carter Hughes. lamo ^1.50 

HULME. — Worked Examination Questions in Plane Geomet- 
rical Drawing : 
For the Use of Candidates for the Royal Military Academy, Wool- 
wich; the Royal Military College, Sandhurst ; the Indian Civil Er.- 
gineering College, Cooper's Hill ; Indian Public Works and Tele- 
graph Departments ; Royal Marine Ll<,'ht Infantry; the Oxford and 
Cambridge Local Examinations, etc. By F. Edward Hulme, F. L. 
S., F. S. A., Art-Master Marlborough College. Illustrated by 300 
examples. Small quarto o fl-KO 

JERVIS.— Railroad Property: 

A Treatise on the Construction and Management of Railways; 
designed to afford useful knowledge, in the popular style, to the 
holders of this class of property ; as well as Railway Managers, Offi' 
cers, and Agents. By JOHN B. Jervis, late Civil Engineer of the 
Hudson River Railroad, Croton Aqueduct, etc. i2mo., cloth ^2.oc 

KEENE.— A Hand-Book of Practical Gauging: 

For the Use of Beginners, to which is added a Chapter on Distilla- 
tion, describing the process in operation at the Custom-House for 
ascertaining the Strength of Wines. By James B. Keene, of H. M. 
Customs. 8vo. . . ... . . . . $1.00 

KELLEY. — Speeches, Addresses, and Letters on Industrial and 
Financial Questions : 
By Hon. William D. Kelley, M. C. 544 pages, 8vo. . ^2.50 

KELLOGG. — A New Monetary System : 
The only means of Securing the respective Rights of Labor and 
Property, and of Protecting the Public from Financial Revulsions. 
By Edward Kellogg. i2mo. Paper cover, $1.00. Bound in 
cloth I1.25 

KEMLO. — Watch- Repairer's Hand-Book: 
Being a Complete Guide to the Young Beginner, in Taking Apart 
PiUting Together, and Thoroughly Cleaning the English Lever and 
other Foreign Watches, and all American Watches. By F. Kemlo, 
Practical Watchmaker. With Illustrations. i2mo. . ;?i.25 



t6 HENRY CAREY BAIRD & CO.'S CATALOGUE. 

KENTISH.— A Treatise on a Box of Instruments, 

And the Slide Rule ; with the Theory of Trigonometry and Log* 
rithms, including Practical Geometry, Surveying, Measuring of Tim., 
bar, Cask and Malt Gauging, Heights, and Distances. By Thoma.' 
Kentish. In one volume. i2mo. . . . . $i.oo 

KERL. — The Assayer's Manual: 

An Abridged Treatise on the Docimastic Examination of Ores, and 
Furnace and other Artificial Products. By Bruno Kerl, Professor 
in the Royal School of Mines. Translated from the German by 
William T. Brannt. Second American edition, edited with Ex- 
tensive Additions by F. Lynwood Garrison, Mem.ber of the 
American Institute of Mining Engineers, etc. Illustrated by 87 en- 
gravings. 8vo. (Scarce.^ 
KICK.— Flour Manufacture. 
A Treatise on Milling Science and Practice. By Frederick Kick 
Imperial Regierungsrath, Professor of Mechanical Technology in the 
imperial German Polytechnic Institute, Prague. TransLnted from 
the second enlarged and revised edition with supplement by H. H. 
P. PowLES, Assoc. Memb. Institution of Civil Engineers. Illustrated 
with 28 Plates, and 167 Wood-cuts. 367 pages. 8vo. . ;^lo.oo 
KINGZETT.— The History, Products, and Processes of the 
Alkali Trade : 
Including the most Recent Improvements. By Charles Thomas 
^' •• ■.7F,TT. Consulting Chemist. With 23 illustrations. 8vo. $2.SQ 
KIRK.— The Cupola Furnace: 

A Practical Treatise on the Construction and Management of Foundry 
Cupolas. By Edward Kirk, Practical Moulder and Melter, Con- 
sulting Expert in Melting. Illustrated by 78 engravings. Second 
Edition, revised and enlarged. 450 pages. 8vo. 1903. $3-50 

LANDRIN.— A Treatise on Steel : 

Cumprising its Tiieory, Metallurgy, Properties, Practical Working, 
ami Use. By M. H. C. Landrin, Jr. From the French, by A. A. 

Fesquet. i2mo I2.50 

LANGBEIN.— A Complete Treatise on the Electro-Deposi. 
tion of Metals : 
Comprising Electro-Plating and Galvanoplastic Operations, the De- 
position of Metals by the Contact and Immersion Processes, the Color- 
ing of Metals, the Methods of Grinding and Polistiing, as well as 
Descriptions of the Electric Elements, Dynamo-Electnc Machines, 
Thermo-Piles and of the Materials and Processes used in Every De- 
partment of the Art. From the German of Dr. George Langbein, 
with additions by Wm. T. Brannt. Fourth Edition, thoroughly reviseu 
and much enlarged. 150 Engravings. 590pages. 8vo. 1902. ^$4.00 

LARDNER.— The Steam-Engine : 

For the Use of Beginners. Illustrated. i2mo. . , , ,60 
LEHNER.— The Manufacture of Inks 

Comprising the Raw Materials, and the Preparation df Waiting, 
Copying and Hektograph Inks, Safety Inks, Ink Extracts and Pow- 
ders, etc. Translated from the German of SiGMUND Lehner, with 
additions by William T. Brannt. Illustrated. i2mo. Sz.ixj 



•'HENRY CAREV BAIRD & CO.'S CATALOGUE. 17 

LARKIN. — The Practical Brass and Iron Founder's Guide.- 

A Concise Treatise on Brass Foundirtg, Moulding, the Metals and 
their Alloys, etc.; to wnicii are added Recent Improvements in the 
Manufacture of Iron, Steel by the Bessemer Process, etc., etc. By 
James Larkin, late Conductor of the Brass Foundry Department ia 
Reany, Neafie & Co.'s Penn Works, Philadelphia. New edition, 
revised, with extensive additions. 414 pages. i2mo. , ^2,50 

LEROUX.— A Practical Treatise on the Manufacture of 
Worsteds and Carded Yarns : 
Comprising Practical Mechanics, with Rules and Calculations applied 
to Spinning; Sorting, Cleaning, and Scouring Wools; the English 
and French Methods of Combing, Drawing, and Spinning Worsteds, 
and Manufacturing Carded Yarns. Translated from the French of 
Charles Leroux, Mechanical Engineer and Superintendent of a 
Spinning-Mill, by Horatio Paine, M. D., and A. A. Fesquet, 
Chemist and Engineer. Illustrated by twelve large Plates. To which 
is added an Appendix, containing Extracts from the Reports of the 
International Jury, and of the Artisans selected by the Committer 
appointed by the Council of the Society of Arts, London, on Woolen 
and Worsted Machinery and Fabrics, as exhibited in the Paris Uni- 
versal Exposition, 1867. 8vo. ..... $$.o<i 

LEFFEL.— The Construction of Mill-Dams : 
Comprising also the Building of Race and Reservoir Embankments 
and Head-Gates, the Measurement of Streams, Gauging of Water 
Supply, etc. By jAMES Leffel & Co. Illustrated by 58 engravings. 
8vo. ^2.50 

LESLIE.— Complete Cookery: 
Directions for Cookery in its Various Branches. By Miss Leslie. 
Sixtieth . thoasand. Thoroughly revised, with the addition of New 
Receipts. i2mo. ... . $i-SO 

LE VAN. — The Steam Engine and the Indicator: 

Their Origin and Progressive Development ; including the Most 
Recent Examples of Steam and Gas Motors, together with the Indi- 
cator, its Principles, its Utility, and its Application. By William 
Barnet Le'Van. Illustrated by 205 Engravings, chiefly of Indi- 
cator-Cards. 469 pp. 8vo. ...... ^4-00 

LIEBER.— Assayer's Guide ; 
Or, Practical Directions to Assayers, Miners, and Smelters, for the 
Tests and Assays, by Heat and by Wet Processes, for the Ores of al! 
tlf principal Metals, of Gold and Silver Coins and Alloys, and of 
Coal, etc. By Oscar M. Lieber. Revised. 283 pp. i2mG. ^1.50 

Suockwood's Dictionary of Terms : 

Used in the Practice of Mechanical Engineering, embracing those 
Current in the Drawing Office, Pattern Shop, Foundry, Fitting, Turn- 
ing, Smith's and Boiler Shops, etc., etc., comprising upwards of Six 
Thousand D«^finitions. Edited by a Foreman Pattern Maker, autho« 
of " Patterr Making." 417 pp. l2mo. . . . ^3-75 



18 HENRY CAREY BAlRD & CO.'S CATALOGUE. 

LUKIN.— The Lathe and Its Uses : 

Or Instruction in tlie Art of Turning Wood and Metal. Including 
a Description of the Most Modern Appliances for the Ornamentation 
of Plane and Curved Surfaces, an Entirely Novel B'orm of Lathe 
for Eccentric and Rose-Engine Turning; A Lathe and Planing 
Machine Combined; and Other Valuable Matter Relating to the 
Art. Illustrated by 462 engravings. Seventh edition. 315 pages. 
8vo $4.2$ 

MAIN and BROWN. — Questions on Subjects Connected witb 
the Marine Steam-Engine : 

And Examination Papers; with Hints for their Solution. By 
Thomas J. Main, Professor of Mathematics, Royal "Maval College, 
and Thomas Brown, Chief Engineer, R. N. i2mo., cloth. ;gi.oo 

MAIN and BROWN. — The Indicator and Dynamometer: 
With their Practical Applications to the Steam-Engine. By THOMAS 
J. Main, M. A. F. R., Ass't S. Professor Royal Naval College, 
Portsmouth, and Thomas Brown, Assoc. Inst. C. E., Chief Engineer 
R. N., attached to the R. N. College. Illustrated. 8vo. . 

MAIN and BRO\A^N.— The Marine Steam-Engine. 

By Thomas J. Main, F. R. Ass't S. Mathematical Professor at the 
Royal Naval College, Portsmouth, and Thomas Brown, Assoc. 
Inst. C. E., Chief Engineer R. N. Attached to the Royal Naval 
College, With numerous illustrations. 8vo. 

MAKINS.— A Manual of Metallurgy: 

By George Hogarth Makins. 100 engravings. Second edition 
rewritten and much enlarged. i2mo. 592 pages 

MARTIN.— Screw-Cutting Tables, for the Use Jf Mechanica) 

Engineers : 
Shownig the Proper Arrangement of (iVheels for Cutting the Threads 
of Screws of any Required Pitch ; with a Table for Making the Uni- 
versal Gas-Pipe Thread and Taps. By W. A. Martin, Engineer. 

8vo. .50 

MICHELL.— Mine Drainage: 
Being a Complete and Practical Treatise on Direct-Acting Und» 
grcund Steam Pumping Machinery. With a Description of a large 
number of the best known Engines, their General Utility and Ihe 
Special Sphere of the,ir Action, the Mode of their Application, and! 
their Merits compared with other Pumping Machinery. By STEPHEN 
MiCHELL. Illustrated by 247 engravings. 8vo., 369 pages. $1250 
MOLESWORTH.— Pocket-Book of Useful Formulae and 
Memoranda for Civil and Mechanical Engineers. 
By Guilford L. Molesworth, Member of the Institution of Civil 
Engineers, Chief Resident Engineer of the Ceylon Railway. Full- 
bound in Pocket-book form . . ... • . $1.00 



HENRY CAREY BAIRD & CO.'S CATALOGUE. tf 

UOORE.— The Universal Assistant and the Complete Bit 

chanic : 

Containing over one million Industrial Facts, Calculations, ReceiptS; 
Processes, Trades Secrets, Rules, Business Forms, Legal Items, Etc., 
in every occupation, from the Household to the Manufactory. By 
R. Moore. Illustrated by 500 Engravings. i2mo. . $2.50 

MI ORRIS. — Easy Rules for the Maasurement of Earthworks : 
By means of the Prismoidal Formula. Illustrated with Numerouf 
Wood-Cuts, Problems, and Examples, and concluded by an Exten- 
sive Table for finding the Solidity in cubic yards from Mean Areas 
The vt^hole being adapted for convenient use by Engineers, Surveyors; 
Contractors, and others needing Correct Measurements of Earthv/ork. 
By Elwood Morris, C. E. 8vo i^i-SC 

MAUCHLINE.— The Mine Foreman's Hand-Book 

Of Practical and Theoretical I-^.formation on the Opening, Venti- 
lating, and Working of Collieries^ Questions and Answers on Prac- 
tical and Theoretical Coal Mining. Designed to Assist Students and 
Others in Passing Examinations for Mine Foremanships. By 
Robert Mauchline, Ex-Inspector of Mines. A Nev/, Revised and 
Enlarged Edition. Illustrated by 1 14 engrarings. 8vo. 337 
pages I3.75 

MAPIER. — A System of Chemistry Applied to Dyeing. 
By James Napier, F. C. S. A New and Thoroughly Revised Edi- 
lion. Completely brought up to the present state of the vScience, 
including the Chemistry of Coal Tar Colors, by A. A. Fesquet,. 
Chemist and Engineer. With an Appendix on Dyeing and Caiicc 
Printing, as shown at the Universal Exposition, Paris, 1867. Illus- 
trated. 8vo. 422 pages ^3.00 

NEVILLE. — Hydraulic Tables, Coefficients, and Formulae, foi 
finding the Discharge of Water from Orifices, Notches, 
Weirs, Pipes, and Rivers : 
Third Edition, with Additions, consisting of New Formulae for the 
Discharge from Tidal and Flood Sluices and Siphons ; general infor- 
mation on Rainfall, Catchment-Basins, Drainage, Sewerage, Water 
Supply for Towns and Mill Power, Bv Tohn Neville. C. E. M R 
I, A. ; Fellow of the Royal Geological Society of Ireland. Thicit 
I2mo ^5.50 

NEW^BERY. — Gleanings from Ornamental Art of every 
style : 
Drawn from Examples in the British, South Kensington, Indian, 
Crystal Palace, and other Museums, the Exhibitions of 1851 and 
1862, and the best English and Foreign works. In a series of loa 
exquisitely drawn Plates, containing many hundred examples. B* 
Robert Newbery. 4to. ...... (Scarce.)' 

NICHOLLS. —The Theoretical and Practical Boiler>Maker ani 
Engineer's Reference Book: 
Containing a variety of Useful Information for Employers of Labor. 
Foremen a'*d Working Boiler-Makers. IroQ, Copper, and Tinsnutltf 



20 HENRY CAREY BAIRD & CO.'S CATALOGUE. 

Draughtsmen, Engineers, the General Steam-using Public, and for the 
Use of Science Schools and Classes. By Samuel Nicholls. IUuS" 
trated by sixteen plaies, 1 2mo. ^2.50 

NICHOLSON.— A Manual of the Art of Bookbinding : 
Containing full instructions in the different Branches of Forwarding, 
Gilding, and Finishing. Also, the Art of Marbling Book-edges and 
Paper. By James B. Nicholson. Illustrated. i2mo., cloth ^2.25 

NICOLLS.— The Railway Builder: 

A Hand-Book for Estiniiiting the Probable Cost of American Rail- 
way Construction and Equipment. By WiLLlAM J. NiCOLLS, Civil 
Engineer. Illustrated, full bound, pocket-book form . J?2.00 

NORMANDY. — The Commercial Handbook of Chemical An« 
alysis : 
Or Practical Instructions for the Determination of the Intrinsic oi 
Commercial Value of Substances used in Manufactures, in Trades, 
and in the Arts. By A. Normandy. New Edition, Enlarged, and 
to a great extent rewritten. By Henry M. Noad, Ph.D., F.R.S., 
thick i2mo. . . . Scarce 

NORRIS. — A Handbook for Locomotive Engineers and Ma- 
chinists : 
Comprising the Proportions and Calculations for Constructing Loco- 
motives; Manner of Setting Valves; Tables of Squares, Cubes, Areas, 
etc., etc. By Septimus Norris, M. E. New edition. Illustrated, 
I2mo $i-S^ 

NYSTROM. — A New Treatise on Elements of Mechanics : 
Establishing Strict Precision in the Meaning of Dynamical Terms; 
accompanied with an Appendix on Duodenal Arithmetic and Me 
trology. By John W. Nystrom, C. E. Illustrated. 8vo. $3.0* 

NYSTROM. — On Technological Education and the Construc- 
tion of Ships and Screw Propellers : 
For Naval and Marine Engineers. By John W. Nystrom, lati 
Acting Chief Engineer, U. S. N. Second edition, revised, with addi 
tional matter. Illustrated by seven engravings. i2mo. . ^i-2_ 

O'NEILL. — A Dictionary of Dyeing and Calico Printing: 
Containing a brief account of all fhe Substances and Processes it 
use in the Art of Dyeing and Printing Textile Fabrics ; with Practical 
Receipts and Scientific Information. By Charles O'Neill, Analy- 
tical Chemist. To which is added an Essay on Coal Tar Colors and 
their application to Dyeing and Calico Printing. By A. A. Fesquet, 
Chemist and Engineer. With an appendix on Dyeing and Calico 
Printing, as shown at the Universal Exposition, Paris, 1867- 8vo., 
491 pages . . ^3.00 

CRTON. — Underground Treasures*. 

How and Where to Find Them. A Key for the Ready Determination 
ui all the Useful Minerals within the United States. By James 
OSTON, A.M., Late Professor of Natural History in Vassar College, 
N. Y ; author of the " Andes and the Amazon," etc. A New Edi- 
tion, witli An Appendix on Ore Deposits and Testing Minerals (1901). 
Illustrated . ' $l-SO 



HENRY CARIiY BAIRD Sc CO.'S CATALOGUE. 



21 



OSBORN.— The Prospector's Field Book and Guide. 

In the Searcli For and the Easy Determination of Ores and Other 
Useful Minerals. By Prof. H. S. Osborn, LL. D. Illustrated by 58 
Engravings. i2mo. Fifth Edition. Revised and Enlarged 
(1901) |i.50 

OSBORN — A Practical Manual of Minerals, Mines and Mm 
ing: 
Comprising the Physical Properties, Geologic Positions, Local Occur- 
rence and Associations of the Useful Minerals; their Methods of 
Chemical Analysis and Assay ; together with Various Systems of Ex- 
cavatmg and Timbering, Brick and Masonry Work, during Driving, 
Lining, Bracing and other Operations, etc. By Prof. H. S. OsBORN, 
LL. D., Author of " The Prospector's Field-Book and Guide." 171 
engravings. Second Edition, revised. 8vo. . . . $^.$0 
OVERMAN. — Th(i Manufacture of Steel : 
Containing the Practice and Principles of Working and Making Steel. 
A Handbook for Blacksmiths and Workers in Steel and Iron, Wagon 
Makers, Die Sinkers, Cutlers, and Manufacturers of Files and Hard- 
ware, of Steel and Iron, and for Men of Science and Art. By 
Frederick Overman, Mining Engineer, Author of the " Manu- 
facture of Iron," etc. A new, enlarged, and revised Edition. By 
A. A. FESQl/iLT, Chemist and Engineer. i2mo. . . ^1.50 
OVERMAN. — The Moulder's and Founder's Pocket Guide : 
A Treatise or. Moulding and Founding in Green-sand, Dry-sand, Loam, 
and Cement; the Moulding of Machine Frames, Mill-gear, Hollow- 
ware, Ornaments, Trinkets, Bells, and Statues; Description of Moulds 
for Iron, Bronze, Brass, and other Metals; Plaster of Paris, Sulphur, 
Wax, etc. ; the Construction of Melting Furnaces, the Melting and 
Founding of Metals ; the Composition of Alloys and their Nature, 
etc., etc. By Frederick Overman, M. E. A new Edition, to 
which is added a Supplement on Statuary and Ornamental Moulding, 
Ordnance, Malleable Iron Castings, etc. By A. A. Fesquet, Chem- 
ist and Engineer. Illustrated by 44 engravings. l2mo. . ^2.00 
PAINTER, GILDER, AND VARNISHER'S COMPANION, 
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ing, Graining, Marbling, Staining, Sign- writing, Varnishing, Glass- 
staining, and Gilding on Glass ; together with Coach Painting and 
Varnishing, and the Principles of the Harmony and Contrast of 
Colors. Twenty-seventh Edition. Revised, Enlarged, and in great 
part Rewritten. By William T. Brannt, Editor of " Varnishes, 
Lacquers, Printing Inks and Sealing Waxes." Illustrated. 395 pp. 

I2mo. . . . , $l.SO 

PALLETT.— The Miller's, Millwright's, and Engineer's Guide. 
Bv Henry Pallett. Illustrated. i2mo. . . . iSa.oo 



22 riENRY CAREY BAIRD & CO.'S CATALOGUE. 

PERCY.— The Manufacture of Russian Sheet-Iron. 
By John Percy, M. D., F. R. S. Paper. ... 25 cts. 

PERKINS.— Gas and Ventilation: 

Practical Treatise on Gas and Ventilation, Illustrated. l2mo. ^1.25 

PERKINS AND STOWE.— A New Guide to the Sheet-iron 
and Boiler Plate Roller : 
Containing a Series of Tables showing the Weight of Slabs and Piles 
to Produce Boiler Plates, and of the Weight of Piles and the Sizes of 
Bars to produce Sheet-iron ; the Thickness of the Bar Gauge 
in decimals ; the Weight per foot, and the Thickness on the Bar or 
Wire Gauge of the fractional parts of an inch; the Weight per 
sheet, and the Thickness on tlie Whe Gauge of Sheet-iron of various 
dimensions to weigh 112 lbs. per bundle; and the conversion of 
Short Weight into Long Weight, and Long Weight into Short. 

POSSELT. — Recent Improvements in Textile Machinery Re- 
lating to Weaving : 

Giving the Most Modern Points on the Construction of all Kinds 
of Looms, Warpers, Beamers, Slashers, Winders, Spoolers, Reeds, 
Temples, Shuttles, Bobbins, Heddles, Heddle Frames, Pickers, 
Jacquards, Card Stampers, etc., etc. 600 illus. . . $3 00 

POSSELT. — Technology of Textile Design: 
The Most Complete Treatise on the Construction and Application 
of Weaves for all Textile Fabrics and the Analysis of Clotii. By E. 

A. Posselt. 1,500 illustrations. 4to ^S-OO 

POSSELT. — Textile Calculations: 

A Guide to Calculations Relating to the Manufacture of all Kinds 
of Yarns and Fabrics, the Analysis of Cloth, Speed, Power and Belt 
Calculations. By E. A. PosSELT. Illustrated. 4to. . $2.00 
REGNAULT.— Elements of Chemistry: 
By M. V. Regnault. Translated from the French by T. FoRREST 
Betton, M. D., a«d edited, with Notes, by James C. Booth, Melter 
and Refiner U. S. Mint, and William L. Faber, Metallurgist and 
Mining Engineer. Illustrated by nearly 700 wood-engravings. Com- 
prising nearly 1,500 pages. In two volumes, 8vo., cloth . S6.00 
RICHARDS.— Aluminium : 

Its History, Occurrence, Properties, Metallurgy and Applications, 
including its Alloys. By Joseph W. Richards, A. C, Chemist and 
Practical Metallurgist, Member of the Deutsche Chemische Gesell- 
schaft. Illust. Third edition, enlarged and revised (1895) . ^6.00 
'RIFFAULT, VERGNAUD, and TOUSSAINT.— A Practical 
Treatise on the Manufacture of Colors for Painting : 
Comprising the Origin, Definition, and Classification of Colors; the 
Treatment of the Raw Materials ; the best Formulae and the Newest 
Processes for the Preparation of every description of Pigment, and 
the Necessary Apparatus and Directions for its Use ; Dryers ; tha 
Testing. Application, and Qualities of Paints, etc., etc. By MM. 
RiFFAULT, Vergnaud, and ToussAiNT. Revised and Edited by M. 



HENRY CAREY BAIRD & CO. S CATALOGUE. 23 



F. Malepsyre. Traniiated from the French, by A. A. FESfj-armiy 
Chemist and Engineer. Illustrated by Eighty engravings. In one 
vol., 8vo., 659 pages ....-•• $S-^^ 

ROPER. — Catechism for Steam Engineers and Electricians: 

Inchiding the Constiuciion and Mauageinent of isieam Engines, 
Steam Bi-ilersand Electric Plants. By STEPHfcN Roper. Tvveniy- 
first edition, rewritten anil greatly enlarged by E. R. Kellkr and 
C. VV. Pike. 365 page.s. Illustrations. i8u)o., tucks, gilt. |2.oo 

ROPER.— Engineer's Handy Book: 

Containing Facts, Formulae, I'ables and Questions on Power, its 
Generation, Transmission and Measurement; Heat, Fuel, and Steam; 
The Steam Boiler and Accessories ; Steam Engines and their Parts ; 
Steam Engine Indicator; Gas and Gasoline Engines; Materials; 
their Properties and Strength ; Together with a Discussion of the Fun- 
damental Experiments in Electricity, and an Explanation of Dynamos, 
Motors, Batteries, etc., and Rules for Calculating Sizes of Wires. By 
Stephen Roper. 15th edition. Revised and enlarged by E. R. 
Keller, M. E. and C. W. Pike, B. S. (1899), with numerous illus- 
trations. Pocket-book form. Leather f3-50 

ROPER. — Hand-Book of Land and Marine Engines : 
Including the Modelling, Construction, Running, and Management 
of Lanr" and Marine Engines and Boilers. With il'ustrations. Bf 
Stephen Roper, Engineer. Sixth edition. i2mo.,ti'cks, gilt edge. 

ROPER.— Hand-Book of the Locomotive : 

Including the Construction of Engines and Boilers, and the Construc- 
tion, Management, and Running of Locomotives. By Stephen 
Roper. Eleventh edition. i8mo., tucks, gilt edge . $2.^(i 

ROPER. — Hand-Book of Modern Steam Fi.'-e-Engines. 
With illustrations. By Stephen Roper, Engineer. Fourth edition, 
i2mo., tucks, gilt edge ....... ^3-50 

ROPER. — Questions and Answers for Engineers. 

This little book contains all the Questions that Engineers will be 
asked when undergoing an Examination for the purpose of procuring 
Licenses, and they are so plain that any Engineer or Fireman of or 
dinary intelligence may commit them to memory in a short time. By 
Stephen Roper, Engineer. Third edition . . . $2.00 
ROPER.— Use and Abuse of the Steam Boiler. 

By Stephen Roper, Engineer. Eighth edition, with illustrations. 

l8mo,, tucks, gilt edge ;5!2.0C 

ROSE. — The Complete Practical Machinist : 

Embracing Lathe Work, Vise Work, Drills and Drilling, Taps and 
Dies, Hardening and Tempering, the Making and Use of Tools 
Tool Grinding, Marking out Work, Machine Tools, etc. By JoSHUA 
Rose. 39s Engravings. Nineteenth Edition, greatly Enlarged with 
New and Valuable Matter. l2mo., 504 pages. . , ^2.50 

ROSE. — Mechanical Drawing Self-Taught : 

Comprising Instructions in the Selection and Preparation of Drawing 
Instruments, Elementary Instruction in Practical Mechanical Draw- 



24 HENRY CAREY BAIRD & CO.'S CATALOGUE. 



i"g) together with Examples in Simple Geometry and Elementary 
Mechanism, including Screw Threads, Gear Wheels, Mechanical 
Motions, Engines and Boilers. By JoSHUA RosE, M. E. Illuslrated 
by 330 engravings. 8vo , 313 pages .... ^4.00 

ROSE.— The Slide- Valve Practically Explained: 

Embracing simple and complete Practical Demonstrations of th« 
operation of each element in a Slide-valve Movement, and illustrat- 
ing the effects of Variations in their Proportions by examples care, 
fully selected from the most recent and successful practice. By 
. Joshua Rose, M. E. Illustrated by 35 engravings . ^r.oo 

I ROSS. — The Blowpipe in Chemistry, Mineralogy and Geology: 
Containing all Known Methods of Anhydrous Analysis, many Work- 
ing Examples, and Instructions for Making Apparatus. By Lieut.- 
CoLONEL W. A. Ross, R. A., F. G. S. With 120 Illustrations. 

i2mo ^2.00 

SHAW. — Civil Architecture : 

Being a Complete Theoretical and Practical System of Building, con- 
taining the Fundamental Principles of the Art. By Edward Shaw, 
Architect. To which is added a Treatise on Gothic Architecture, etc. 
By Thomas W. Sili.oway and George M. Harding, Architects. 
The whole illustrated by 102 quarto plates finely engraved on copper. 
Eleventh edition. 4to. ....... ^6.00 

SKUNK. — A Practical Treatise on Railway Curves and Loca- 
tion, for Young Engineers. 

By W. F. Shunk, C. E. l2mo. JuU bound pocket-book form ;^2.oo 
SLATER.— The Manual of Colors and Dye Wares. 

By J. W. Slater. i2mo. ...... i^3.oo 

SLOAN. — American Houses : 

A variety of Original Desis^ns for Rural Buildings. Illustrated by 
26 colored engravings, with descriptive references. By Samuel 
Sloan, Architect. 8vo. .75 

SLOAN. — Homestead Architecture : 

C'jntainir.g Forty Designs for Villas, Cottages, and Farm-houses, with 
Eisays on Style, Construction, Landscape Gardening, Furniture, etc., 
etc. Illustrated by upwards of 200 engravings. By Samuel Sloan, 
Architect. 8vo. ... ..... IS2.50 

SLOANE. — Ho.re Experiments m Science. 

By T. O'CoNOR SLC4.NE, E. M., A.M., F:-.. O. Illustrated by 91 
engravings. i2mo. ....... |>l.oo 

SMEATON.— Builder's PocktSCompanion : 

V Containing the Elements of Building, Surveying, and Architecture; 
with Practical Rules and Instructions cor.''ected with the subject. 

» By A. C. Smeaton, Civil Engineer, etc. l2mo. 

SMITH. — A Manual of Political Economy. 

By E. Peshine Smith. A New Edition, to which is added a full 
Index. i2mo. $1-25 



HENRY CAREY LaIRD & CO.'S CATALOGUE. 25 

SMITH.— Parks and Pleasure- Grounds : 

Or Practical Notes on Country Residences, Villas, Public Parks, and 
Gardens. By Charles H. J. Smith, Landscape Gardener and 
Garden Architect, etc., etc. i2mo. .... ^2.oc» 

SMITH.— The Dyer's Instructor: 

Comprising Practical Instructions in the Art of Dyeing Silk, Cotton^^ 
Wool, and Worsted, and Woolen Goods ; containing nearly 8oo( 
Receipts. To which is added a Treatise on the Art of Padding; an(^ 
the Printing of Silk Warps, Skeins, and Handkerchiefs, and the! 
various Mordants and Colors for the different styles of such work* 

, By David Smith, Pattern Dyer. lamo. . . . ^1.50/ 

SMYTH. — A Rudimentary Treatise on Coal and Coal-Mining. 
By Warrington W. Smyth, M. A., F. R. G., President R. G. S.i 
of Cornwall. Fifth edition, revised and corrected. With numer- 
ous illustrations. i2mo. ...... $'^•7^ 

SNIVELY. — Tables for Systematic Qualitative Chemical AnaU 
ysis. 
By John H. Snively, Phr. D. 8vo. .... ^i.oo 

SNIVELY. — The Elements of Systematic Qualitative w-hemical 
Analysis : 
A Hand-book for Beginners. By John H. Snively, Phr. D. i6mo. 

^2.00 

STOKES. — The Cabinet-Maker and Upholsterer's Companion : 
Comprising the Art of Drawing, as applicable to Cabinet Work; 
Veneering, Inlaying, and Buhl- Work; the Art of Dyeing and Stain 
ing Wood, Ivory, Bone, Tortoise-Shell, etc. Directions for Lacker- 
ing, Japanning, and Vi.rnishing; to make French Polish, Glues, 
Cements, and Compos'. j ns; with numerous Receipts, useful to work 
men generally. Bv Stokes. Illustrated. A New Edition, with 
an Appendix upor .ench Polishing, Staining, Imitating, Varnishing, 
etc., etc. i2nio #1.25 

STRENGTH AND OTHER PROPERTIES OF METALS; 
Reports of Experiments on the Strength and other Properties of 
Metals for Cannon. With a Description of the Machines for Testing 
Metals, and of the Classification of Cannon in service. By Officers 
of the Ordnance Department, U. S. Army. By authority of the Secre- 
tary of War. Illustrated by 25 large steel plates. Quarto . ^5-00 

SULLIVAN. — Protection to Native Industry. 
By Sir Edward Sullivan, Baronet, author of " Ten Chapters 011 
Social Reforms." 8vo , ;^i,OQ 

SHERRATT.— The Elements of Hand-Railing : 

Simplified and Explained in Concise Problems that are Easily Under- 
stood,. The whole illustrated with Thirty-eight Accurate and Origi- 
nal Plates, Founded on Geometrical Principles, and Showing how to 
Make Rail Without Centre Joints, Making Better Rail of the Same 
Material, with Half the Labor, and Showing How to Lay Out Stairs 
of all Kinds. By R, J. Sherratt. Folio. . . . ;^2.5o 



2fi HENRY CAREY BAIRu & CO.'S CATALOGUE. 

SYME. — Outlines of an Industrial Science. 

By Daviu Syme. i2mo, . . ... $2.00 

TABLES SHOWING THE WEIGHT OF ROUND, 
SQUARE, AND FLAT BAR IRON, STEEL, ETC., 

By Measurement. Clolh ...... 63 

THALLNER.— Tool-Steel : 

~ A Concise Handbook on Tool-Steel in General. Its Treatment in 
the Operations of Forging, Annealing, Hardening, Tempering, etc., 
and the Appliances Therefor. By OxTO Thallner, Manager in 
Chief of the Tool-Steel Works, Bismarckhiitte, Germany. From the 
German by VVilliam T. Brannt. Illustrated by 69 engravings. 
194 pages. 8vo. 1902. ...... |2.oo 

TEMPLETON. — The Practical Examinator on Steam and th^ 
Steam -Engine : 
With Instructive References relative thereto, arranged for the Use of 
Engineers, Students, and others. By William Templeton, En- 
gineer. i2mo. ........ Ii.oo 

THAUSING.— The Theory and Practice of the Preparation of 
Malt and the Fabrication of Beer: 
With especial reference to the Vienna Process of Brewing. Elab- 
orated from personal experience by JuLlUS E. Thausing, Professor 
at the School for Brewers, and at the Agricultural Institute, Modling, 
near Vienna. Translated from the German by WiLLiAM T, Brannt, 
Thoroughly and elaborately edited, with much American matter, and 
according to the latest and most Scientific Practice, by A. ScHWARZ 
and Dr. A. H. Bauer. Illustrated by 140 Engravings. 8vo., 811; 
pages ^10.00 

THOMPSON.— Political Economy. With Especial Reference 
to the Industrial History of Nations : 
By Robert E, Thompson, M. A., Professor of Social Science in the 
University of Pennsylvania. i2mo. .... ^1.50 

THOMSON.— Freight Charges Calculator: 

By Andrew Thomson, Freight Agent. 24mo. . . ^1.25 

TURNER'S (THE) COMPANION: 
Containing Instructions in Concentric, Elliptic, and Eccentric Turn. 
ing; also various Plates of Chucks, Tools, and Instruments; and 
Directions for using the Eccentric Cutter, Drill, Vertical Cutter, and 
Circular Rest; with Patterns and Instructions for woiking them, 
l2mo. . $1.00 

TURNING : Specimens of Fancy Turning Executed on the 

Hand or Foot- Lathe : 

With Geometric, Oval, and Eccentric Chucks, and Elliptical Cutting 

Frame. By an Amateur. Illustrated by 30 exquisite Photographs. 

4to J2.50 



HEKRY CAREY BAIRB & CO.'S CATALOGUE. 27 



^AILE. — Galvanized- Iron Cornice-Worker's Manual: 

Containing Instructions in Laying out the Different Mitres, and 
Making Patterns for all kinds of Plain and Circular Work. Also, 
Tables of Weights, Areas and Circumferences of Circles, and other 
Matter calculated to Benefit the Trade. By Charles A. Vaile. 
Illustrated by twenty-one plates. 4to ^5.00 

VILLE. — On Artificial Manures : 

Their Chemical Selection and Scientific Application to Agriculture. 
A series of Lectures given at the Experimental Farm at Vincennes, 
during 1867 and 1874-75. By M. Georges Ville. Translated and 
Edited by William Crookes, F. R. S. Illustrated by thirty-one 
engravinus. 8vo., 450 pages ...... $6,00 

VILLE.— The School of Chemical Manures : 
Or, Elementary Principles in the Use of Fertilizing Agents. From 
the French of M. Geo. Ville, by A. A. Fesquet, Chemist and En- 
gineer. With Illustrations. i2mo. . , . . ^1.25 

VOGDES. — The Architect's and Builder's Pocket- Companioa 
and Price-Book : 

Consisting of a Shoit but Comprehensive Epitome of Decimals, Duo- 
decimals, Geometry and Mensuration ; with Tables of United States 
Measures, Sizes, Weights, Strengths, etc., of Iron, Wood, Stone, 
Brick, Cement and Concretes, Quantities of Materials in given Sizes 
and Dimensions of Wood, Brick and Stone; and full and complete 
Bills of Prices for Carpenter's Work and Painting; also. Rules for 
Computing and Valuing Brick and Brick Work, Stone Work, Paint- 
ing, Plastering, with a Vocabulary of Technical Terms, etc. By 
Frank W. Vogdes, Architect, Indianapolis, Ind. Enlarged, revised, 
and corrected. In one volume, 368 pages, full-bound, pocket-book 
form, gilt edges ........ ^2.00 

Cloth . . 1.50 

VAN CLEVE.— The English and American Mechanic : 

Comprising a Collection of Over Three Thousand Receipts, Rules, 
and Tables, designed for the Use of every Mechanic and Manufac- 
turer. By B. Frank Van Cleve. Illustrated. 500 pp. i2mo. ^2.00 

VAN DER BURG.— School of Painting for the Imitation of 

Woods and Marbles : 

A Complete, Practical Treatise on the Art and Craft of Graining and 

Marbling with the Tools and Appliances. 36 plates. Folio, 12x20 

inches #10.00 

WAHNSCHAFFE.— A Guide to the Scientific Examinatioo 
of Soils : 
Comprising Select Methods of Mechanical and Chemical Analyst 
and Physical Investigation. Translated from the German of Dr. F. 
Wahnschaffe. With additions by William T. Brannt. Illus- 
irated by 25 engravings. l2mo. 177 pages . . . #1.50 

WALTON. — Coal-Mining Described and Illustrated: 
By Thomas H. Walton, Mining Engineer. Illustrated by 24 lax^ 
and elaborate Plates, after Actual Workings and Apparatus. ^5.00 



2S liENRY CAREY BAIRD & CO.'S CATALOGUE. 

WARE.— The Sugar Beet. 

Including a History of the Beet Sugar Industry in Europe, Varietie 
of the Sugar Beet, Examination, Soils, Tillage, Seeds and Sowing, 
Yield and Cost of Cultivation, Harvesting, Transportation, Conserva 
tion, Feeding Qualities of the Beet and of the Pulp, etc. By Lewu 
S. Ware, C. E., M. E. Illustrated by ninety engravings. 8vo. 

^4.00 
WARN. — The Sheet-Metal Worker's Instructor: 

For Zinc, Sheet-Iron, Copper, and Tin-Plate Workers, etc. Contain- 
ing a selection of Geometrical ProMems ; also. Practical and Simple 
Rules for Describing the various Patterns required in the different 
branches of the above Trades. By Reuben H. Warn, Practical 
Tin-Plate Worker. To which is added an Appendix, containing 
Instructions for Boiler- Making, Mensuration of Surfaces and Solids, 
Rules for Calculating the Weights of different Figures of Iron and 
Steel, Tables of the Weights of Iron, Steel, etc. Illustrated by thirty- 
two Plates and thirty-seven Wood Engravings. 8vo. . ^3.00 

WARNER. — New Theorems, Tables, and Diagrams, for the 
Computation of Earth-work : 

Designed for the use of Engineers in Preliminary and Final Estimates 
of Students in Engineering, and of Contractors and other non-profes. 
sional Computers. In two parts, with an Appendix. Part I. A Prac- 
tical Treatise; Part II. A Theoretical Treatise, and the Appendix. 
Containing Notes to the Rules and Examples of Part I.; Explana- 
tions of the Construction of Scales, Tables, and Diagrams, and a 
Treatise upon Equivalent Square Bases and Equivalent Level Heighta 
By John Warner, A. M., Mining and Mechanical Engineer. Illus- 
trated by 14 Plates. 8vo. |53.oo 

WILSON. — Carpentry and Joinery. 

By John Wilson, Lecturer on Building Construction, Carpentry and 
Joinery, etc., in the Manchester Technical School. Third Edition, 
with 65 full page plates, in flexible cover, oblong . . .80 

WATSON. — A Manual of the Hand-Lathe : 

Comprising Concise Directions for Working Metals of all kinds, 
Ivory, Bone and Precious Woods; Dyeing, Coloring, and French 
Polishing; Inlaying by Veneers, and various methods practised to 
produce Elaborate work with Dispatch, and at Small Expense. By 
Egbert P. Watson, Author of " The Modern Practice of American 
Machinists and Engineers." Illustrated by 78 engravings. ^1.50 

WATSON. — The Modern Practice of American Machinists and 
Engineers 
Including the Construction, Application, and Use of Drills, Latlie 
Tools, Cutters for Boring Cylinders, and Hollow-work generally , with 
the most Economical Speed for the same; the Results verified bj 
Actual Practice at the Lathe, the Vise, and on the Floor. Togethen 



HENRY CAREY BAIRD & CO.'S CATALOGUE. 29 

with Workshop Management, Economy of Manufacture, the Steam 
Engine, Boilers, Gears, Belting, etc., etc. By Egbert P. Watson. 
Illustra'ed by eighty-six engravings. l2mo. . . . $2.50 

WATT.— The Art of Soap Making : 

A Practical Hand-Book of the Manufacture of Hard and Soft Soaps, 
Toilet Soaps, etc. Fifth Edition, Revised, to which is added an 
Appendix on Modern Candle Making. By Alexander Watt. 
111. i2mo ^3.00 

WEATHERLY.— Treatise on the Art of Boiling Sugar, Crys- 
tallizing, Lozenge-making, Comfits, Gum Goods, 
And other processes tor Confectionery, etc., in which are explained, 
in an easy and familiar manner, the various Methods of Manufactur- 
ing every Description of Raw and Refined Sugar Goods, as sold by 
Confectioners and others. l2mo. ..... ^1.50 

WILL,.— Tables of Qualitative Chemical Analysis : 

With an Introductory Chapter on the Course of rinalysis. By Pro- 
fessor Heinrich Will, of Giessen, Germany. Third American, 
from the eleventh German edition. Edited by Charles F. Himes, 
Ph. D., Professor of Natural Science, Dickinson College, Carlisle, 
Pa. 8vo. ^1.50 

WILLIAMS.— On Heat and Steam : 

Embracing New Views of Vaporization, Condensation and Explo- 
sion. By Charles Wye Williams, A. I. C. E. Illustrated. 8vo. 

^2.50 

WILSON. — First Principles of Political Economy: 

With Reference to Statesmanship and the Progress of Civilization. 
By Professor W. D. Wilson, of the Cornell University. A new and 
revised edition. i2mo. ....... ^1.50 

WILSON.— The Practical Tool-Maker and Designer: 

A Treatise upon the Designing of Tools and Fixtures for Machine 
Tools and Metal Working Machinery, Comprising Modern Examples 
of Machines with Fundamental Designs for Tools for tlie Actual Pro- 
duction of the work; Together with Special Reference to a Set of 
Tools for Machining the Various Parts of a Bicycle. Illustrated by 
189 engravings. 1898. ....... ^$2.50 

CONTENTS : Introductory. Chapter I. Modern Tool Room and Equipment. 
II. Files, Their Use and Abuse. III. Steel and Tempering. IV. Making Jigs. 
V. Milling Machine Fixtures. VI. Tools and Fixtures for Screw Machines. VII. 
Broaching. VIII. Punches and Dies for Cutting and Drop Press. IX. Tools for 
Hollow-Ware. X. Embossing : Metal, Coin, and Stamped Sheet-Metal Orna- 
ments. XI. Drop Forging. XII. Solid Drawn Shells or Ferrules; Cupping or 
Cutting, and Drawing ; Breaking Down Shells. XIII. Annealing, Pickling and 
Cleaning. XIV. Tools for IVaw Bench. XV. Cutting and Assembling Pieces 
by Means of Ratchet Dial Plates at One Operation. XVI. The Header. XVII. 
Tools for Fox Lathe. XVIII. Suggestions for a Set of Tools for Machining the 
Various Parts of a Bicycle. XIX. The Plater's Dynamo. XX. Conclusion — 
With a Few Random Ideas. Appendix. Index. 

WOODS. — Compound Locomotives: 

By Arthur Tannatt Woods. Second edition, revised and enlarged 
by David Leonard Barnes, A. M., C. E. 8vo. 330 pp. $s<x 



30 HENRY CAREY BAIRD & CO.'S CATALOGUE. 

WOHLER.— A Hand-Bookof Mineral Analysis: 

By F. W5HLER, Professor of Chemistry in the University of Gottin- 
gen. Edited by Henry B. Nason, Professor of Chemistry in the 
Renssalaer Polytechnic Institute, Troy, New York. Illustrated. 
i2mo. 

WORSSAM.— On Mechanical Saws: 

From the Transactions of the Society of Engineers, 1869. By S. W. 
WoRssAM, Jr. Illustrated by eighteen large plates. 8vo. J^l.50 



RECENT ADDITIONS. 

BRANNT. — Varnishes, Lacquers, Printing Inks and Sealing-* 
Waxes : 

Their Raw Materials and their Manufacture, to which is added the 
Art of Varnishing and Lacquering, including the Preparation of Put- 
ties and of Stains for Wood, Ivory, Bone, Horn, and Leather. By 
William T. Brannt. Illustrated by 39 Engravings, 338 pages. 
i2mo. .......... ^3.00 

BRANNT — The Practical Scourer and Garment Dyer: 

Comprising Dry or Chemical Cleaning; the Art of Removing Stains; 
Fine Washing ; Bleaching and Dyeing of Straw Hnts, Gloves, and 
Feathers of all kinds; Dyeing ot V\^orn Clothes of all fabrics, in- 
cluding Mixed Goods, by One Dip; and the Manufacture of Soaps 
and Fluids for Cleansing Purposes. Edited by William T. Brannt, 
Editor of " The Techno-Chemical Receipt Book." Illustrated. 
203 pages. i2mo. ^2.00 

BRANNT.— Petroleum . 

its History, Origin, Occurrence, Production, Physical and Chemical 
Constitution, Technology, Examination and Uses; Together with 
the Occurrence and Uses of Natural Gas. Edited chiefly from the 
German of Prof. Hans Hoefer and Dr. Alexander Veith, by Wm. 
T. Brannt. Illustrated by 3 Plates and 284 Engravings. 743 pp. 
8vo. ^^7.50 

BRANNT. — A Practical Treatise on the Manufacture of Vine- 
gar and Acetates, Cider, and Fruit-Wines ; 
Preservation of Fruits and Vegetables by Canning and Evaporation ; 
Preparation of Fruit-Butters, Jellies, Marmalades, Catchups, Pickles, 
Mustards, etc. Edited from various sources. By WiLLIAM T. 
Brannt. Illustrated by 79 Engravings. 479 pp. 8vo, ^6.00 

BRANNT.— The Metal Worker's Handy-Book of Receipts 
and Processes : 

Being a Collection of Chemical Formulas and Practical Manipula- 
tions for the working of all Metals ; including the Decoration and 
Beautifying of Articles Manufactured therefrom, as well as their 
Preservation. Edited from various sources. By WiLLIAM T. 
Brannt. Illustrated. i2mo. ^2.50 



HENRY CAREY BAIRD & CO.'S CATALOGUE 31 

DEITE. — A Practical Treatise on the Manufacture of Per- 
fumery : 

Comprising directions for making all kinds of Perfumes, Sacliet 
Powders, Fumigating Materials, Dentifrices, Cosmetics, etc., with a 
full account of the Volatile Oils, Balsams, Resins, and other Natural 
and Artificial Perfume-substances, including the Manufacture of 
P'ruit Ethers, and tests of their purity. By Dr. C. Deite, assisted 
by L. BoRCHERT, F. Eichbaum, E. Kugler, H. Toeffner, and 
other experts. From the German, by Wm. T. Brannt. 28 Engrav- 
ings. 358 pages. 8vo. $3-'^° 

EDWARDS. — American Marine Engineer, Theoretical and 
Practical : 
With Examples of the latest and most approved American Practice. 
By Emory Edwards. 85 illustrations. i2mo. . . ^2.50 

EDWARDS. — 900 Examination Questions and Answers: 

For Engineers and Firemen (Land and Marine) who desire to ob- 
tain a United States Government or State License. Pocket-book 
form, gilt edge ........ $1-5^ 

FLEMMING.— Practical Tanning. 

By Louis A. Flemming, an American Practical Tanner. 450 pages. 
8vo. (1903) .... ^4.00 

POSSELT. — The Jacquard Machine Analysed and Explained: 

With an Appendix on the Preparation of Jacquard Cards, and 
Practical Hints to Learners of Jacquard Designihg. By E. A. 
Posselt. With 230 illustrations and numerous diagrams. 127 pp. 
4to $30Q 

POSSELT.— The Structure of Fibres, Yarns and Fabrics: 

Being a Practical Treatise for the Use of all Persons Employed in 
the Manufacture of Textile Fabrics, containing a Description of the 
Growth and Manipulation of Cotton, Wool, Worsted, Silk Flax, 
Jute, Ramie, China Grass and Hemp, and Dealing with all Manu- 
facturers' Calculations for Every Class of Material, also Giving 
Minute Details for the Structure of all kinds of Textile Fabrics, and 
an Appendix of Arithmetic, specially adapted for Textile Purposes. 
By E. A. Posselt. Over 400 Illustrations, quarto. . $S-00 

RICH. — Artistic Horse-Shoeing: 

A Practical and Scientific Treatise, giving Improved Methods of 
Shoeing, with Special Directions for Shaping Shoes to Cure Different 
Diseases of the Foot, and for the Correction of Faulty Action in 
Trotters. By George E. Rich. 62 Illustrations. 153 pages 
l2mo> $1.00 



32 HENRY CAREY BAIRD & CO.'S CATALOGUE. 

RICH ARDSON.— Practical Blacksmithing : 

A Collection of Articles Contributed at Different Times by Skilled 
Workmen to the columns of "The Blacksmith and Wheelwright," 
and Covering nearly the Whole Range of Blacksmithing, from the 
Simplest Job of Work to some of the Most Complex Forgings. 
Compiled and Edited by M. T. Richardson. 

Vol.1. 2IO Illustraiions. 224 pages. l2mo. , . ;^i.oo 

Vol. II. 230 Illustrations. 262 pages. lamo. . . |i.oo 
Vol. III. 390 Illustrations. 307 pages. i2mo. . . ^i.oo 
Vol. IV. 226 Illustrations. 276 pages. l2mo. . . jjSl.oo 
RICH ARDSON.— The Practical Horseshoer: 

Being a Collection of Articles on Horseshoeing in all its Branches' 
which have appeared from time to time in the columns of " '! he 
Blacksmith and Wheelwright," etc. Compiled and edited by M. T. 
Richardson. 174 illustrations ^i.oo 

ROPER. — Instructions and Suggestions for Engineers and 
Firemen : 
Ky Stephen Roper, Engineer. i8mo. Morocco . ^2.00 
ROPER. — The Steam Boiler: Its Care and Management: 

By Stephen Roper, Engineer. i2mo., tuck, gilt edges. ^2.00 

ROPER.— The Young Engineer's Own Book: 

Containing an Explanation of the Principle and Theories on which 
the Steam Engine as a Prime Mover is Based. By Stephen Roper, 
Engineer. 160 illustrations, 363 pages. i8mo., tuck . $2.50 

ROSE. — Modern Steam-Engines: 

An Elementary Treatise upon the Steam-Engine, written in Plain 
language ; for Use in the Workshop as well as in the Drawing Office. 
Giving Full Explanation i of the Construction of Modern Steanv 
Engines : Including Diagrams showing their Actual operation. To- 
gether with Complete bat Simple Explanations of the operations of 
Various Kinds of Valves, Valve Motions, and Link Motions, etc., 
thereby Enabling the Ordinary Engineer to clearly Understand the 
Principles Involved in their Construction and Use, and to Plot out 
their Movements upon the Drawing Board. By Joshua .R.DSE. M. E. 
Illustrated by 422 engravings. Revised. 358 pp. . . ^6.00 

ROSE. — Steam Boilers: 
A Practical Treatise on Boiler Construction and Examrnation, for the 
Use of Practical Boiler Makers, Boiler Users, and lAspectors; and 
embracing in plain figures all the calculations necessary in Designing 
or Classifying Steam Boilers. By Joshua Rose, M. E. Illustrated 
by 73 engravings. 250 pages. 8vo. .... ^2.50 

SCHRIBER. — The Complete Carriage and Wagon Painter: 
A Concise Compendium of the Art of Painting Carriages, Wagons, 
and Sleighs, embracing Full Directions in all the Various Branches, 
including Lettering, Scrolhng, lujmanienting. Striping, Varnishing, 
and Coloring, with numerous Recipes for Mixing Color*. 73 Illus- 
tratjons. 177 pp. i2mo. . . . . . $i.nc 



